I like middleweights like the CB 500. The problem is the A2 category which puts a silly restriction on them. I had a GPz 500S for a number of years and it did a lot of hard work including the Bol d'Or a few times two up with full camping gear. It was not short of power or speed. The CB500 looks a good choice with a decent dual seat and almost certainly would be a decent ride but it's need to sell into the A2 market probably means it will not ignite a lot of souls.
My current ride is the GSX650F which used to be a bandit but you must never say so. It was in two versions A2 and full power. Needless to say I have the latter. It is a decent ride but would benefit from an aftermarket seat for long journies. The motor is more "Honda" in that it will ride all day long at low revs - say up to 5k - and perform like a commuter or you can open it up and it is more like a Suzuki. Its good for at least 130 two up at which point I had to slow for a corner so there was - I am sure - more to give.
Cheap too and good mpg. When I was a kid this would have been a "big" bike.
A had a 750 gixer before when we lives in Sussex and the handling was much sharper but the licence shredding effect much higher. (Had an MV Augusta F4 and sold it sharpish for that reason) I like Woz's Aprilia but my licence would not. I have been (casually) looking for a 'new' bike for a number of years but cannot justify anything I see. The trend to a much higher pillion is annoying for two up and I get bored stopping every 300 meters to wait for the missus to catch up on her Monster.