Can someone remind me why shimano 7 speed is a hassle?
They could only do that if it was. You're rather unlikely to come across UniGlide (used for 6-speed and early 7-speed) unless you deliberately go looking for it. Nearly everything 7-speed you come across will be HyperGlide. You need a spacer to use 7-speed HG cassettes on 8-11 speed HG freehubs, but then you need a spacer on half the 10-speed cassettes too and very few people died.
Are UniGlides the ones that the bottom/smallest cog acts the lock-ring and you need 2 chain whips to get them off? Trying to source sprockets myself, knowing the name helps
They could only do that if it was. You're rather unlikely to come across UniGlide (used for 6-speed and early 7-speed) unless you deliberately go looking for it. Nearly everything 7-speed you come across will be HyperGlide. You need a spacer to use 7-speed HG cassettes on 8-11 speed HG freehubs, but then you need a spacer on half the 10-speed cassettes too and very few people died.