Both HoN and DotA2 are games full of small differences. Being a native DotA player since the early 2000s when DotA got started, I remember quite vividly exactly how the game was when I left it for HoN. Since I played HoN, frankly, I haven't looked back- I could never again get used to the graphics, the UI, the clunky gameplay. As DotA2 came along and upgraded all of the above the same way HoN did, returning to DotA seemed like stepping into a parallel dimension- a blast from the past.
For me, returning to the "DotA world" was a very interesting experience, because I started noticing all these changes- not just largescale changes like Alchemist's Unstable Concoction being reworked from a channeling ability to an instant cast "countdown" mechanic, but also smaller, much more subtle differences. Now, it could be that a lot of these small differences are actually things that HoN changed and DotA never did- my memory is not perfect and I don't remember exactly how many things were changed within DotA while I was gone compared to things HoN changed for some reason. But what I do know is that these small subtle differences make a huge difference in the way Heroes work in the game, and that many people take these subtle things for granted. So off the top of my head, enjoy this little list of cool little things I've noticed.
Anti-Mage versus Magebane
While both Heroes are relatively the same concept (hard carry with blink mechanic, no real CC or way of keeping the enemy still) they carry with them some unique characteristics. First of all, Magebane's Spell shield is combined with his Flash ability. When this ability was first put into the game, a lot of people were upset because it seemed really overpowered. After all, it meant that not only Magebane got to benefit from his already strong anti-magic shield, but now his whole team did, too? Sounds OP. But in reality, the change ended up being more of a Nerf than a Buff. How? Simple- since Magebane had to Blink in order to provide the shield for anyone, it meant that if enemies could sneak up on him, he wouldn't have any protection at all. Because of this, Magebane is much more susceptible to Ganks, whereas Anti-Mage is protected constantly. Seeing as how survivability in Carries is extremely important to craddle them into the lategame, it comes to no surprise that this is a very important difference between the two. Of course, it also helps that HoN has a lot more brutal gankers out there- Fayde specifically really butchers Magebane with her two abilities which burn his Mana. Another interesting difference between the two (aside from the passive on on Magebane which Anti-Mage doesn't have) is the cast point on their ultimates. Magebane's ultimate takes years to cast in comparison with Anti-Mage's ultimate, which goes off seemingly instantly. The fraction of a second extra that Magebane needs to cast his ultimate makes all the difference in the world- as it means that Anti-Mage has a much more powerful tool for killing wounded Heroes in the Early to Mid game. Magebane's ultimate, on the other hand, has such an unbearably long cast time that it's almost a skill shot if you don't have clearvision.
Lina's a little on the Slow Side
Back when I left, I think Icefrog was still trying to figure out what he wanted to do with Lina's third ability. Back then, it was an activatable ability that gave you a lot of attack speed. The ability didn't really synergize with Lina very much, as she was a caster, and built her items around having a larger Mana Pool, more HP, etc- but not +damage. As such, the increased Attack Speed wasn't really very significant and a lot of people didn't even end up picking up the skill at all. Somewhere between then and now, both DotA and HoN have opted for a passive ability instead, that procs when you cast spells. Arguably, the HoN passive is better in every aspect. It gives Pyromancer a Damage over Time on every single attack, which is invaluable for preventing enemies from using potions, plus it provides significant damage to buildings and Kongor. But really, the unsung Hero of this entire deal is the increased cast time. Lina's Light Strike Array is, in fact, so incredibly difficult to land with her casting animation half the time, that the small increase in cast time that only 1 rank of Fervor provides seems to completely negate the brutal cast time. Indeed, in Heroes of Newerth Pyromancer's 1 rank of Fervor that is often picked up early seems to make all the difference in landing his spells more reliably- and turns him into quite a monster in the later game.
A Bloody little Pat on the Back
Blood Hunter is sort of like the younger, physically handicapped cousin of Blood Seeker. Although seemingly better in every aspect, Blood Hunter somehow manages to be a bottom-of-the-barrel pick in HoN. Even lower level pubs are hesitant to pick him up these days, I personally can't even remember the last time I've seen him. And yet, for some reason, Blood Seeker, the Hero that seemingly does everything Blood Hunter does and worse, is a decent pick, at least from what I can see in current DotA2 pub games. So what's the deal? Where did Blood Hunter go wrong? Different metagame, easier to counter, better alternatives? Maybe- but really, the most distinct difference is in the itemization: Blood Hunter has no good mid-game items for him besides Mock, which is pretty darn difficult to farm in a real game. Blood Seeker, on the other hand, will be all too happy to pick up a Force Staff- an item that increases his ganking potency drastically. Funny how one item can make such a difference, but Force Staff works with Rupture in DotA, whereas Tablet of Command doesn't do anything for Blood Hunter. With one click Blood Seeker can launch his enemies helplessly in a direction, providing them an untimely advance in their menstrual cycle. The extra burst damage this provides seems to really make a difference in the games I've been in, and really helps Blood Hunter to dominate the mid-game if he plays his cards right.
Back To The Dumpster
Chronos and Faceless Void have always sort of been the staple of a "Hard Carry" in both games, and, while I can't really speak for DotA, Chronos seemingly has always been either complete rubbish or totally overpowered. It seems like no matter what S2 does, he's always either too good or too shitty. Returning to DotA2, I can't help but feel like DotA has done a better job taking care of everybody's favorite deaf, blind, purple time traveling alien. Faceless Void seems to out perform Chronos even though they're extremely similar in every way. Two subtle changes seem to make all the difference, at least for me: For one thing, Faceless Void can Bash you randomly at any time. Chronos needs a bit of a warm up and will only bash you every 5 hits, a prospect that doesn't seem like much of a threat compared to a static 25% Bash with no cooldown. This alone makes a huge difference, not just because of the lack of stun on Chronos but also the extra bonus damage that Faceless Void gets during his Chronosphere, which brings us to point #2- Chronosphere's duration. Chronosphere (DotA version) has a 4 second Duration at rank one, which scales only 0.5s a rank to 5 seconds at rank 3. Chronofield on the other hand, only freezes time for 3 seconds at rank 1, adding an extra second every rank. This seemingly small difference makes a huge difference in the early game. While Chronos might like to boast that his Time Leap deals damage, this small early game advantage is easily overshadowed by Faceless Void's massive 4 second Stun combined with a very reliable Bash that hits hard.
I'm sure other players who are currently undergoing the same transition will have their own small differences to write about. Flint outclassing Sniper due to his Flare over Shrapnel, Pharaoh's Wall of Mummies that seemingly suck everything in a thousand mile radius into them, Necrolyte's permanent 1000 range Heartstopper Aura- all of these subtle small differences completely make or break Heroes!