I enjoyed the movie but my only drawback is that the final battle with the main villain was weak.

I actually like that, the battle was more about the army and firepower he commands rather than the guy himself, not every Marvel villain needs to be a god or whatever. Besides, for as hateable as he was, seeing him get his ass whooped was rather cathartic.

I just felt the power scale was off, the main villain can easily destroy the 'golden kid', and that kid easily took down the whole Guardian team.  Yet the Guardians beat the villain so quick and easily? It just didn't feel believable.

Because the High Evolutionary has power over gravity, and that's his only power. The Guardians all have gravity boots, Adam does not. Also Adam never tried attacking him, he was caught off-guard (whereas the Guardians in the end all get the jump on him).

I don't think the movie was ever trying to do things like a 'power scale'.

So his abilities are nothing like the comic book? (or if they are he just never used them on the Guardians?)

The battle just seemed a little too quick and easy that's all.

I know nothing about the character in the comic book so I'll leave that to you.

The battle was definitely quick and easy and I've explained why I liked it better that way. I definitely understand why some would find it disappointing. Agree to disagree, I suppose.

I would say that when Adam Warlock attacked the guardians, they were caught off guard and fighting him individually, whereas in the end battle, they were all united. 

Which one? Warlock or High Evolutionary?

If Warlock, he's high end below the cosmic gods but higher than pretty much all earth based heroes and most beings in the entire universe. If High Evolutionary... he's high end below the cosmic gods but higher than pretty much all earth based heroes and most beings in the entire universe. :P

Both would hold their own against Galactus but would lose (ignoring more recent events as Marvel power scaling went nuts not long ago, terrible writers).

Both have levels of telepathy that would make most fights meaningless in the MCU.

Will admit, not read any comics since the dispute, and Disney purchased Fox since then.

They also stated in the movie that Warlock was taken out prematurely so he is not as powerful as he should have been.

I think that's just an explanation for his behavior, I didn't take it to mean that he'd become more powerful. Though obviously he'd be better at fighting with more experience and knowledge.