I am enjoying my analog system, but what can I do to improve?

If the rest of the system is capable, the SP10 has weight and authority, bass is well defined and timing/separation is good. Basically high on PRAT. Again its not massively better. The 1200G is a good deck, to step up from there you need to be looking at serious kit. The laws of diminishing returns means improvements will be small, but costs will be high.
And a well set up 1200G will always sound better than a poorly set up SP10 of course (Arm/Cartridge dependant).
For anyone starting without a Turntable, or stepping up from a modestly priced one, the 1200G represents a large outlay. A  previously owned SP10 has more potential in my opinion and a decent example of a MkII could be had for a lot less money.
If you already have a 1200G then this would not be a good move financially and more of a sideways step performance wise.
I heard a Mk5 and SP10 in the same set up, both good examples, with decent cartridges and arms. The SP10 was slightly better but not by much.
Though, to be fair, Mk5 had bearing, power supply and platter upgrades.

Dear @qwin : " All the Technics DD turntables are Coreless are they not? "

Only the Technics new line of TT. As I posted not even the SP10MK3 is coreless motor design. Yes the vintage SP10 is a better performer even with no coreless motor but for other design and build reasons.

Here the today " SP10 " and remember that specs does not " sounds ":

R.

R.

@chungjh  : Please read in that Technics link all the times Technics mention the TT model you own and that was used as reference for the top fligth model.

R.

qwin, After your last one or two posts, I am no longer certain what is your position. The SP10 Mk3 is simply in another league from either the SL1200 Mk2 or the 1200G series, BUT, as Raul already mentioned, no Technics turntable used a coreless motor before they introduced the current G series and the SP10R. Your 1200 Mk2 has an iron core motor, as did all other Technics tables of the earlier era. If you want to make a comparison of old vs new Technics, you would compare the new SP10R (top of the line, coreless motor) to the SP10 Mk3 (top of the vintage line, most powerful iron core motor ever used in a commercial DD TT). When I say "powerful", I am referring to torque. The high torque of the Mk3 motor was needed to control its 21-lb platter. I have owned SP10 Mk2 (two samples) and I currently own and use a Mk3. The latter is a more neutral sounding turntable. I am sure the SP10R is competitive with the Mk3. All of these need a proper plinth (but "proper" is another debatable adjective). The way you talk about the SL1200 Mk2 vs the 1200G, it seems you own or have owned both. Is that the case? If so, which version of the G series? Thanks.

Coreless motors ought to be inherently superior for use in a DD turntable because of the lack of cogging, but their drawback is they need to be physically large to produce a lot of torque and they produce heat as they get more powerful. In the vintage era, Kenwood, Yamaha, and Pioneer, at least, marketed turntables with coreless motors. Probably there were others that escape my memory. The iron core SP10 Mk3 motor uses 12 iron core poles. The more poles, the smoother the ride, the lower the problem of cogging. That’s another way to approach the issue.

Not sure where this thread is going versus the original question...but if the new question is 'do higher quality turntable systems sound better than what OP has' the answer is YES, costs and diminishing returns aside. Top Micro, Top Technics, CS Port, Gran Prix, Dohmann, and etc.

Maybe easier to parce options if a budget range were developed.