You can still change out the arm on a 1200G if the stock arm does not do it for you. I think the stock arm is very good and a fantastic value and very versatile.
This not a sort of turntable to change tonearms, it's too complicated. But Technics tonearm is great to swap the cartridges quickly. I've been using Technics SL1210mkII since 1995, just bored of its design and limitations. But for begginers GR it's amazing turntable. I love Techniques for its build quality, it's bulletproof turntable, this is the reason why i don't like cheap belt-drive turntables flooded the market.
you cannot put a 12 inch arm or 3 arms on it and I guess that is a compromise of sorts. However, some do not need 3 arms and the 1200G gives a great performance of a very high end turntable for a fraction of the cost of a sp-10R. its still not inexpensive3 arms at the same time is a perversion (imo). Using a high compliance (40-50cu @ 10Hz) unit on Technics tonearm is not good, much lighter tonearm required for them. Using an SPU or related low compliance (10-15cu @ 10Hz) on Technics tonearm is also perversion. The rest of the carts works fine on it.
But even SP-10R is not as good in terms of usability as Luxman PD-444 for two tonearms, i don't like the desing of the SP-10R plinth, power supply and even tonearm. Luxman's metal armboards on slide with bracket is an amazing solution for people who's searching for the right arm/cart combo. I can swap the tonearm in 10 min. Designer of Luxman PD-444 is genius! This superheavy turntable cost $2000-4000 depends on condition and sound quality is amazing. So in my world Technics SL1200G can't compete with Luxman PD-444 (thanks Micro Seiki for it).
The only problem is that my Technics EPA-100mk2 can not be mounted on Luxman :(
No problem with the rest of the arms from my small collection.
I'm sure the PD-444 is the best value product on the market for people who would like to use two tonearms at the same time.