Could we see any full-service airlines from Eastern Europe operating to MAN? LOT (to WAW), Czech Airlines (to PRG), TAROM (to OTP), Bulgaria Air (to SOF)?
All four of these carriers have served these very routes in times past. They eventually succumbed to competition from more nimble no-frills competitors (from LPL as well as MAN). Three of those four cities are now served from MAN by no-frills carriers, so there would be robust competition to contend with. Czech Airlines has now repositioned itself as a no-frills operation in its own right, even down to serving unlikely obscure airports.
The "logistical headache" of re-positioning BA aircraft to be based out of MAN is actually not that hard.
But it is also not a compelling proposition when they can just leave the heavy lifting to their codeshare partner and close buddy American Airlines. It is certainly less hard for them.
MAN - DXB (Using QF Metal)
Aircraft enthusiasts would welcome this, but what is in it for the airline? High-volume bookings already come in via the existing codeshare arrangements.
It did not work with SAA but should do with the right aircraft
Actually, SAA did fine on MAN-JNB/CPT for several years. Everything changed when international sanctions against South Africa were lifted following the abolition of Apartheid. Overnight, a world of international opportunities opened up to SAA's limited fleet resources. New glamorous global destinations were launched, MAN made way. Of course, today's SAA is a very different beast and the market has changed beyond recognition. The VFR market has collapsed (more dramatically than Canada). The draw for South Africa now has to be tourism-driven, but some of its cities are today considered very high risk for visitors from a safety perspective.
Bangkok - as mentioned, another good TCX route.
Leisure operators such as Thomas Cook and Thomson will likely favour the exotic resorts rather than the capital. An airline such as Thai can offer connections across Thailand from BKK; TCX and TOM cannot do this. The island beaches are the big mass-market draw. However, if they do decide to offer BKK I'll be delighted.
Delhi/Mumbai - quite how AI have not opened this is beyond me. BHX do really well on the route
Ethnic distribution is a key consideration here. Political correctness urges us to speak of "Asians", but Indians, Pakistanis and Bangladeshis are not the same (let alone other nationalities comprising Asia). Birmingham and the Midlands has a very large ethnic Indian population, including a concentration of Sikhs who travel to Amritsar. The North West is home to far more Pakistanis and Bangladeshis, as are some areas of West Yorkshire. There are Indians resident in the NW, but on nothing like the scale of those living around Birmingham Airport's catchment. Having said that, I do believe that MAN could support a service to India (it is a BRIC and a tourism hotspot, after all) but BHX undeniably has the stronger market in this instance.
Air Asia X have sniffed around this route [Kuala Lumpur] but were put off by APD.
Never say never. MAN remains a medium-term objective for Air Asia X according to some informed sources. MAN wasn't top pick in earlier rounds, but it is still on the agenda.