Well, if someone has the right to do a dota game it's Blizzard after all because all the skills and stuff are their idea (most are, many got modified by now but are based on their idea).
What I don't like about their "dota" is, that they'll include Starcraft and Diablo stuff as well, ie. Arthas fighting vs Diablo. I for example never liked Starcraft stuff, but I'm into Warcraft and Diablo though.
AND Blizzard got the money and knowledge to do some great stuff, though they could have done it far earlier; now they noticed that dota games became really popular they want a part of the cake as well.