If you think about it, Valhalla won't end up being a big fraction of Traumerei's power. Traumerei divided his power into far too many entities.
There are 3 that got the biggest chunks: Valhalla, nerfed Traumerei and Leviathan. Nerfed Traumerei is at least comparable to Valhalla, and considering its hype, Leviathan is at least around here as well. Considering just this, Valhalla likely falls around 30% of Traum's full power.
Then there are the other 6 of the 7 animals: Fandore Harpe, Arrogant Kraken, Lazy Elgore, Enraged Rapid, and probably Cobalt and Vanquish. All of them at least pose a threat to CC Tier fighters, with some of them probably standing above. These are all the Shinheuh that he shared a portion of his direct power and abilities with.
But it's still not over because Traum can fuse with all the Shinheuh within All-Creatures, not just his 7 beasts. Just the amount of ancient Shinheuh he gave to Holand already numbers in the tens of thousands, and this is probably not a very relevant fraction of the full number. Among these random Shinheuh, some of them are fairly strong. There's a nameless crocodile that had Goruro (a BH level High Ranker) in awe of its power. There's the megalodon summoned against Gustang that came after Rapid too.
Consider the Shinwonryu release that was about to erase the Nest. Not all of it was released. Sophia came close to her limits after blocking an insignificant fraction of a fraction for a brief amount of time (and just random Shinheuh were unleashed). Traumerei has become one with all this power.
If we want to be picky, all the Shinheuh of the BHs (Wolf, Turtle, Cobra, Eagle Owl, Dobo, Haetae, Gran Abuelo, Percheron, Windbird, Elephant, Carp, Polar Bear, Chupacabra, Badger...) originally belonged to Traumerei and are also part of his power that gets stronger under his control, and that he can absorb.
All things considered, Valhalla would probably be lucky to reach 20% of Traumerei's full power.