You can balance it out a little with Tevals lifelink, but if you get to cast massive spells much earlier in the game, you probably wont care that much about losing a little life early on
Regardless of your commander choice, a committed Transformers theme deck probably wants to focus more on artifact synergies than legendary ones, with a smattering of combat tricks and +1/+1 counter generation
For example, if you own 1 or more cards from the deck, you wont get anything
Regal Behemoth is a great six-mana cost Dinosaur with 5/5 stats and Trample
Merry, Warden of Isengard + Pippin, Warden of Isengard I kind of like the go-wide stuff happening with the Merry, Warden of Isengard and Pippin, Warden of Isengard version of the Food and Fellowship Commander precon, but neither really convinces me
The three modes are a bit disparate for my taste, but its probably worth it if you can snag the Stifle mode and make the other modes matter at the same time