Why do we need an Ulgu Orb of Sorcery? We're not exactly planning on making a battle altar anytime soon. I'd rather give it to the colleges, not just because it's a source of College favour, but because it will be more useful to them than to us.
Why would we not want an Ulgu Orb of sorcery? you never know when you are going to need it and its a huge investment making a new one since we would need to make all 8.
It's not like the colleges are going to use them right away, it would just be stored same as the others, maybe they get more lax on their use since they are no longer relic tier, but whatever the case i say we keep one around, maybe push the limits of our enchanting using it as a power source.
Edit: Way i see it:
The Orbs are like a computer, yes you can fly to the moon without it, but you need a team and years of calculations, and it that same frame, most people can't afford computers even if they already exist, so their use is very controlled and limited.
So, even if you are not planning to go to the moon, there's a lot of stuff you can try with a computer that other people can't because its too expensive or there is a large queue to access it (Yes i had to run simulations for my thesis, why do you ask?), but suddenly that is not a problem and you can now afford to approach a lot of problems from a different angle.
To make it clear, i'm using the computer as an analogue because it seems part of the issue the Orbs solve is one of complexity, you can do a complicate array with powerstones, calculating their interactions among themselves and the environment, or you can plug in an Orb, or better yet, you can see an unsolvable problem that would requiere years of trial and error to even being to approach a solution, or you can merely have a masterwork difficulty problem when using an orb.