The other question i asked earlier, if there are no models for undead or chaos dwarf in the tablet edition, how would i see them?
In order to make the game cross-platform compatible you necessarily have the models for ALL the teams that exist in Chaos Edition. That they only offer 4 teams to purchase beyond the first two is nothing more than artificial scarcity - they could offer all of them today, but it benefits them to release them in small chunks instead of all at once, as doing so drives higher sales for teams that would otherwise sell poorly.
Seeing your previous purchases/teams is probably where I would blame Apple.
It's where I'd "blame" the fact that the tablet version is a direct-as-they-could-manage port of the PC game, using the same code, models, and communication system... and using the same servers for multiplayer matchmaking. I'd also say they simply forgot to put in a restriction on the server to disallow the two versions (PC or tablet) from logging in using the same accounts - something they'll likely rectify in future, because it shows that there is a major flaw in their sales model at the moment.
Of course, when they put in that restriction, it'll be based on voluntary client-side self-identification, just as your access to all the teams in CE is based on voluntary client-side restrictions.. dot dot dot...