Plot hole: Durotan's clan is the Frostwolf clan, orcs who ride big white wolves. The problem is...they are riding those wolves when they are in the human world, but those huge wolves made to be orc mounts were not with them when they crossed the portal from their homeworld. Unless the human world has the same wolves and they managed to tame them in record time, it's inexplicable.
Suggested correction: Once the portal opens hordes of orcs start running into the portal. Just because you didn't see any wolves among them doesn't mean there weren't any. They obviously brought their wolves with them. They probably entered through last along with some food and tools they might need.
We see the portal close once the sorcerer blows life into the baby and the whole invasion force is on screen. Those few warriors are all that comes through the portal, which makes sense given what he said about having limited energy to transfer only a few people.
No, no. I thought you were going to say that. Look at it again, when the portal closes there are orcs standing all around it, cheering. There are hundreds of them, you saw scores of orcs run into the portal as well. Surely there are wolves amongst them as well.
There is a line of orcs around the portal, yes (still few in the context of the invasion), but there are no wolves there either, no wolves heard howling or anything. I don't know: no wolves shown running into the portail, no wolves shown exiting the portal, no wolves standing amongst those around the portal, nor heard, not even with the chieftan of the tribe that rides them. I find it easier to think that they just made them up on the spot in pure "fridge logic" to homage the game (they are not seen in the movie much nor they have a really important role) rather than postulating that perhaps there's a wolf herder guy who brought along a few dozens wolves that happen to be hidden now amongst the trees.
It may be easier to believe that, but doesn't make it impossible. Just because you didn't see them doesn't mean they weren't there. It's plausible, therefore no error and certainly not a plot hole, certainly not since you agree they don't have an important role.
I don't find it plausible since there isn't the faintest hint of it shown in the movie in a scenario where we are supposed to see all their forces: if it did not make such a point of that, I am sure I could agree with you. It's not a matter of filling in blanks left by the movie, it's about contradicting what was on screen. It's easily (or logically, if you will: I use the word 'easily' in an Occam's razor sort of way) explained (and not justified) by the wolves being 'fanservice' homage in a couple scenes, which made them easy to overlook (because they forgot or because they did not care, we can't know that) when it came to planning the invasion scenes. I believe it fits the definition of 'plot hole' because however unimportant and cosmetic of an element it is, giving a character or a group of characters something that was not there before 'breaks' the movie world as represented. I am however fine with any other category, I wouldn't split hairs on that and I welcome your different opinion. :-).
Continuity mistake: When Kadgar is telling Lothar about the great gate and that the Guardian burned his research, both of them go to pick up a chest, which they were doing anyway, but instead the scene switches to them both sitting down to talk, and the chest has gone. (00:52:00)
Revealing mistake: In the opening scenes, we see a very pregnant Draka reclining on a bed of animal hides as Durotan watches over her. In the extreme closeup, we see Draka twitch her lips, and her small tusks flex from side-to-side with her lips, instead of remaining firmly aligned with her jaw as they should.
