Denying is actually one of the main reasons I dislike DotA and HoN so much together with the horrid community, horrible interface and horrible graphics, no, this is not referring to the wc3 graphics, DotA was just a very, very ugly, badly terrained map (which is the only reason juking was even possible). HoN looks "better", but it's cluttered with useless effects - which, in my eyes, is "horrible graphics" as well. In fact, they put me off of the entire AoS genre completely until I started playing LoL.
Honestly, denying isn't especially fun to do; it doesn't feel rewarding from the side doing it as opposed to last hitting - you don't get any shiny gold, you simply deny the others from getting gold. From a global point; it's as rewarding as last hitting, but it doesn't feel even close to as rewarding. Honestly, if they didn't make the exclamation mark appear over a denied unit, you wouldn't feel as if you'd have gotten anything out of it at all.
On the opposing side it does feel punishing on the receiving side - they've just lost gold and experience, meaning they can't get the items and levels that make the game fun for them. This is what's known as a loss-loss situation; it makes the game less fun for one side, and not any more fun for the other, meaning your game has a nett loss of fun.
Furthermore, it creates a gap between good and bad players. A lot of players will go "yea, good players need to shine!" and sure, they should perform better. But if you create so much of these spots where good players gain huge advantages over worse ones to the point where the worse ones can't actually do anything it'll just make them quit your game once and for all. No matter how good the rest of your map is, if they get steamrolled, killed constantly and end up level 5 at the 30 minute mark they will never play your game again. And when one player is so strong that he can 1v5 an entire team (as can be done in DotA and HoN) this is "kinda cool" for that one player, "not fun in the slightest" for the 5 opposing players, and "meh" for the players 4 teammates because they feel as if they're not contributing anything.
If you want to cater to the DotA players, go ahead and add in denying. Just why exactly would they play your map above DotA, HoN, SotIS, Valve's DotA or any of the dozens existing DotA clones?
If you want to cater to newer players, leave out denying and make your map newb friendly. It's up to you.