As to the OPs question, I say keep the LP12 and buy another deck anyway.
Case in point, I was getting ready to throw my LP12 in the bin last night (okay, slight exaggeration) as it just sounds terrible compared to my Technics 1210GR. In fairness, it's more that a lot of my records sound terrible or not enjoyable to listen to through my LP12 (technically speaking, I'm talking LP12 + Tannoys + living room). My better sounding records, mostly pre-digital records, sound great of course. But I've got a lot of modern vinyl that just sound rubbish going on unbearable through my LP12; so much so that I always end up playing the same records over and over, the ones I know that sound great. In contrast, I've yet to hear a bad sounding record on my Technics deck, everything is just so enjoyable.
To cut a long story short, I've aborted plans to use my Technics deck in my bedroom system and instead have returned it to its rightful place in my living room; for some reason, the Technics deck has much more synergy with my bad records and my Tannoys, unlike my LP12 which can only play the good stuff. Seriously, I just can't live with how bad so many of my records sound on my LP12 (LP12 + Tannoys + room), and knowing how good the Technics deck is, well to not use my Technics deck in my main system feels like a form of self-inflicted harm.
The thing is, all my records used to sound good and quite enjoyable before I bought my Tannoys so I know my LP12 has the potential to boogie. So seeing as I do need a turntable in my bedroom, I put my LP12 in there last night and lo and behold, it sounds great. Paired up once again with my Kan-like Kralk Audio BC-30s, the LP12 is in its element and pumping the boogie into my bedroom like it used to do in my living room.
Although my Technics deck sounds great in either room with either system, my LP12 is a poor match with my Tannoys (+room), but it's an excellent match for the bass-lite bookshelf speakers in my bedroom so that's where it's gonna stay. So yeah, OP, buy another deck anyway and see what it brings - you just might end up with the best of both worlds