I hope they are discovered on earth having already been here, (be it searching for the allspark or for some other reason... and that their mech-dino forms are explained as their old way of blending in with the old populous millions of years ago.
May as well be Jurassic Park or Terminator if they have flesh. And while its granted that the Dinobots wouldn't be blending in these days either rendering of surface texture, its be cool to see them not turn this into a generic monster movie. Besides: if we allow for flesh on Dinobots, then Bay might get the hankering for doing....... the Pretenders......
And that clusterf*** has to be avoided....no matter the cost. :P
It would defeat Megatron's "fleshbag/puny flesh creature" rants whilst simultaneously posing the question of: "Why bother generating human looking holograms for cover etc when they could have a real and fleshy part of them for the same purpose.
I can see them taking the alt route of 'Dinobot alt forms for Modern (GMC) cars or military vehicles.'
Think about it, Dinosaurs aren't very intelligent creatures. They rely on their sense of Smell and Hearing above everything else. Their eyesight is pretty damn poor so all the Dinobots would have to do is become vaugely similar shape-wise.
As an answer to their intelligence (though I STILL dislike the idea of the DB's having the cave-man speech) Ratchet could explain that (having been on their own for millions of years) their minds have slowly devolved . Think robot dementia.
they could just have metallic skin that uses holograms to make it look like skin so they could have blended in with the dinosaurs when they arrived, and then say their holo-projectors got damaged by whatever killed the dinosaurs, so we see them with just the metallic covering.
Why not...? It would appear that in these new movies, TFs can actually withstand slamming into the ground at x-amount of hundreds or thousands of miles an hour as meteors themselves without a slight bit of damage, it would seem.
The writers dumped the ark idea because they couldn't see why aliens that moonlighted as vehicles would need a ship to travel through space.
Just three reasons I can think of are:
1) To conserve energy/fuel.
2) To avoid slamming into planets at thousands of miles per hour.
3) The autobots had somewhere to hang out.