Realities of development. Making it both 1st/3rd person would increase the time to make a Reinforcement due to all the extra steps that will need to go in, think Animation etc. It's not that the team didn't want to do it, or lazy as someone I'm sure will say.
I'm simplifying greatly, but for argument's sake let's say you could end up with one of the three situations below:
- 4 Reinforcements with 3rd person only released on Y
- 4 Reinforcements with both 1st/3rd person released on Y+3months
- 2 Reinforcements with both 1st/3rd person released on Y
As always, Game Development is a series of decisions and having to say yes to some thing, no to others. Even if you'd like nothing more than to say yes to everything.