I don't think so. The Governor planned on ambushing Rick at the meeting. Merle took out eight of the Governor's best, not just eight random schmucks. The showdown at the prison could've looked a lot different if Merle hadn't done what he did (and the showdown with Merle could've looked a lot different if Milton hadn't burned the Governor's walker-bomb).
The showdown happened logically ... make it look abandoned, funnel them into a small space, scare the hell out of them and make them flee. They're not soldiers. They have no skills. They've never been in a gunfight. Get them closed-in, make their numbers useless ... and then use their inexperience to your advantage. If Merle hadn't taken down those eight ... there'd probably have been a firefight in the catacombs.
I thought it was a fitting ending ... and I like that the writers don't always take you where you're expecting to go. Everybody expected the Governor, Martinez and the black fella to die ... they didn't. Everybody expected some of the weakest at the prison to fall ... they didn't. Everybody expected Rick's crew would take out a bunch of the Governor's and the Governor himself, and lose a few of their own ... but the Governor took out his own and fled to fight another day, and Rick lost none, and gained several useful people.
And, in contrast to last year's ending which set up what's next ... this ending left you wondering where they're going with it. Keeping people guessing is a good thing.
SnakeDoc
Well stated.