They should make one - it's the last movie and everybody loves the four legged walkers.
The AT-AT is a killer toy and if they scaled it to roughly the same size as the AT-AT I think they'd have a winner.
Same price point as the AT-AT too - $75.
If they can afford to tool the ARC-170 (killer ship BTW) they can afford to do this one.
Though I think they lost their asses on the royal starship - did anyone pay full price for that thing?