Oh yes, that lovely backpack expander. That is somewhat of a exploit of a system that is out of Valve's control, but what does it matter to the customers?
Actually 2 keys yields more credits at TF2WH (22k vs 20k), also keys are less likely to be overstocked (TF2WH takes a maximum 3500 keys compared to 50 expanders)
I don't think the value propositions for champions are that high either. There is a TON of work put into each one.
I have nothing against LoL's system in theory. My problem is that there hasn't been a single champion in the past year who has came out below 4800 or 6300 IP (right around the time Riot was bought by Tencent /tinfoilhat).
Also Riot's IP price reduction plan is currently a joke. They reduced the IP prices of the first set of champions (the ones that were cheaper in the first place) and most recently reduced Irelia and Miss Fortune from 6300 to 4800 IP.
Also this whole conversation may be silly because if Dota 2 takes on a F2P system (it'd be dumb if it didn't!) it'll probably have a very similar structure and pricing system as League.
Dota 2 is all but guaranteed to be F2P, but there is nothing yet that hints you will have to buy characters. Instead it seems like you will buy individual cosmetics (pieces of armor, different looking weapons, etc), taunts, custom couriers and announcer packs