Having played both DotA2 and HoN for a while now, I've observed a few things. Both games aim to improve the functionality of the original DotA by adding new Features and Interfaces aimed at making the game more "DotA player friendly", seeing as how Warcraft 3's interface obviously wasn't designed for DotA alone. And while both games have come far, it seems like both games still have improvements over the other. I feel like both games could learn a thing or two from the other, so here we go:
Things HoN can learn from DotA2
In DotA2, when you have items on the courier and the courier delivers them to your Hero, the game will basically search for every single possible way to combine them in such a way that A) all the items will be on your Hero, combined and B) done all at once, without having to press any buttons more than once. This feature is extremely convenient in DotA2, and consequently, extremely inconvenient in HoN because it doesn't exist. If my Hero in HoN, for example, has 5 random items and one component for 3 component recipe and I have the two other components for the item on the Courier, the Courier will not deliver any items at all and the item will not combine. This is because the courier can only deliver a maximum of one item at a time if my inventory is full, whereas DotA2 basically uses a system that pools all your items together, tries to combine them, and then tries to put them in your inventory. In other words, a lot less scrambling to try and combine stuff together, a lot less headache, a lot smoother gameplay.
"At a Glance" Mana Cost UI
A feature which has been requested for HoN since the dark ages, it's something nobody really knows why it hasn't happened yet. Mana Costs for abilities in DotA2 are displayed in a clean simple manner which does not obscure the icon. By simply looking down at my interface I can easily check how much Mana a spell costs, a feature which provides real benefits in hectic situations where I don't have time to hover over the spell to check. For something that seems like it would only take an hour to implement, S2 seems to persist with the idea that that should be a mod and not a real thing- an opinion I hope will change as they run down their checklist of things to borrow from DotA2. Similarly, the "level pegs" of the ability beneath the icon are equally handy and are definitely something I wouldn't mind seeing in HoN.
Commendations / Karma System
All ARTS games have gameplay which breeds the fabled "bad community" problem. The best way to counter this sort of thing, in my opinion, is to create a system which encourages and incentiveses players to behave better. These "Karma systems" have been heavily requested for Heroes of Newerth for a long time, but the idea has never been taken seriously or implemented. DotA2, on the other hand, is making a distinct effort to better the community- not only is the new Stat screen very selective in which stats it displays (no KDR- thank god) but it also features this Commendation screen where you can commend players for being nice, forgiving, for being a good teacher or displaying leadership. Of course, this feature is still half baked (because the game is in beta), and it remains to see exactly how Valve plan on developing it into a full fetched system, but I for one am already extremely excited and I expect great things in the future.
Things DotA2 can learn from HoN
When HoN first came out, it had very, very, very long tooltips. For new players, these were very intimidating, because it felt like they were reading a book when all they wanted to know was what the ability did. Sometime along HoN 2.0, S2 decided that the old, heavily detailed Tooltips had to be shortened, but at the same time they didn't want to remove crucial information that the player needed. Thankfully, S2 pulled through and created some very sleek yet efficient tooltips which get straight to the point, yet don't leave out valuable information. In most of the cases, these new tooltips kept all the important information including Mana Costs, Cooldowns, Ranges/Radii, etc- but the long tooltips are still available in the menu for people who still prefer them. DotA2 tries to do what S2 did but falls short. The DotA2 tooltips are often short, but they are ruined by the fact that they withhold vital information. Things like Mana Cost and Cooldown are displayed, but often ability-unique numbers and important details like the type of damage (Physical or Magic, etc.) are left out. DotA2 also "lists" the details of the spell in an often long large tooltips, whereas in HoN the numbers are written into the sentence which describes the spell chronologically. And finally, DotA2 features flavor text in their tooltips, something that I personally don't like because it only takes up space and doesn't really contribute anything- Ideally there would be an option to turn these off.
HoN takes care of most problems that players have via a vote. In DotA2, any player can pause the game at any time via the press of a button, something which becomes extremely annoying if somebody feels the need to turn a teamfight into a slideshow. In HoN, when a player wants to pause, 3 of his teammates must agree and then the pause is announced and counted down before the game actually pauses. Similarly, the game will also announce and count down the unpause. It's debatable how and if DotA2 will chose to implement a system like this, but for now its current system definitely seems lackluster. While the Kick option would certainly be a controversial move, I would also argue (and have argued) that a unanimous concede option should also be implemented into DotA2. Similarly, if enough players on both teams agree, a remake vote would also be beneficial to the game.
Sell Items Anywhere
In HoN, you can sell items anywhere on the map, even if they are on your courier and not you. In fact, all you have to do is hold down two buttons and right click the item to make it sell. I don't see why this isn't a feature in DotA2 as I don't think it would influence balance in any meaningful way, all it would do is make the game a lot more convenient for everyone. If you accidentally buy the wrong item in DotA2 with the Courier, you're screwed. There is no way to sell it unless you can teleport back to base in time. One missclick can therefore lose you the game if you accidentally make a Mekansm on Faceless Void by accident, something I don't really feel should be punished as hard as it is. Situations in which you are doing Roshan are often plagued by the fact that you can't simply sell items back to the store, the result is players finding Iron Branches sprinkled across the map.