Isn't that just like LoL then? The only things you pay for are cosmetic changes and rate of experience increases.
Well with LoL you could get IP boosts, which would help you unlock new heroes/runes/runepages. As DOTA 2's entire pool is available from the get-go, there are no runes or runepages, there's no actual in game currency system. You earn Battle Points which just level you up for cosmetic items. You can also randomly find them so I'd say its closer to TF2 than LoL.
Also a major difference between LoL and DOTA 2 (and HoN I suppose) is that you are able to get the skins/cosmetic items without having to pay money. Granted, paying money just gets you them much more readily (though the prices are a quite a bit steeper), I like that you can gain them just from playing the game alot. Not to mention you can trade them with others!