Adding in another ORAS slot would be a good idea; given that OUPL only has 1 ORAS slot, there's a pretty good chance that the pool for OUFL with the current format will be unnecessarily cramped as a good number of solid-to-decent players will end up undrafted in OUPL and will likely just sign up for OUFL afterwards. In just this year alone, the number of active and competent ORASers has grown significantly. Another ORAS slot balances the pool and aligns with the other oldgens.
I don't think removing an SV slot is the worst thing in the world since OUPL is doing 4x anyways, but I think going to 12 slots and adding a Masters Bo3 would be a nice, symmetric alternative.
I'm skeptical regarding arguments that 12 slots is too difficult with respect to slot preparation; that seems to only be the case in situations where we would add in isolated tiers like BW or SV ND. 12 slots with 2x ORAS + 1x Masters Bo3 would (in theory, anyways) allow for the opportunity for more dedicated support across 2 slots + have the first added slot (ORAS) be able to directly contribute to the second added slot (Masters Bo3). Again, obviously the operative word is allow, which does not obligate, but in a tour like OUFL I wouldn't expect any slot to be totally siloed from the others. But the addition of BW or SV ND runs a higher risk of isolation since there's only a single one of them and their cross-slot impact will likely be lesser.
Unrelatedly, whether or not another SV slot is added, maybe consider changing one of them to a Bo3? We did this for the oldgens in RoAPL, and by the end of the tournament it seemed like most players had some fun with it. A little more pressure on your "best" SV slot could be cool.