It does look similar, yes, although based on the description I think it's meant to be the turbolaser mentioned (the 8 heavy lasers would I guess be the 2 ball turrets at the front with another one on the other side, and it looks like there might be an undercarriage turret at the rear, plus one on the back at the top (these would be some of the heavy blaster cannons).
I like the fact that it isn't OGed (Over Gunned) like a lot of fan made things, where people stick guns on an spare surface.
As far as transports go I think the LAATs were more OG'ed than that thing - they could carry what? 10 Clone Troopers aboard? And had how many guns again
? Yes I know that they weren't pure transports, but meh
.
Anyway, a few thoughts of my own...
The good:
-It's already much better armed than the AT-ATs, and its weapons are better positioned, what with those ball turrets.
-Anyone rapelling from the undercarriage will be better protected, thanks to the middle pair of legs and the ball turrets at the front.
-The semi-circular section at the top of the vehicle might be another entry / exit point for personnel or even vehicles (speeders anyone?). This would make it much easier when it comes to assaulting urban environments - stormtroopers could use the upper entrance to enter buildings above the ground level. Against opponents below the AT-BT, it provides cover when entering / exiting the vehicle, and would allow speeders to accelerate a little before leaving the cover of the AT-BT, making them harder to hit.
-It should be able to carry a hell of a lot more stormtroopers than the AT-AT can, unless the weapons, legs and armour require a considerable amount of space inside.
The bad:
-It appears to have several windows at the front - unless the materials used are as good as the main body armour, this could be a problem.
-It still looks vaguely like some sort of giant beast, despite the lack of a head in the same manner as an AT-AT - one of the reasons, I believe, for the AT-AT's design.
-The whole body must turn if it is to fire the turbolaser (assuming that's what the large dorsal weapon is). That said, it looks like the front section of the vehicle may be able to move slightly (look at the differences between the nearest two AT-BTs in the picture).
-The positioning of the turrets at the front leaves both sides unprotected , as the legs are positioned outside the turrets. However, they'd still be fairly well placed to cover any troops disembarking via a hatch in the undercarriage (the legs would also provide cover from the sides).
-The middle pair of legs I'm also not sure about - might they restrict the movement of the vehicle too much? It'd probably need such legs in order to spread its weight though, so possibly it was a compromise design.
-Speaking of weight, it might also be more restricted where it can and cannot be deployed than the AT-AT. It could even be argued that the AT-BT came first, and that the AT-AT was developed after to go where its bigger cousin couldn't.