Upgrade, smaller and lighter, mention ME Super and Super Program . . .
All of these are smaller and lighter except for the LX which is smaller but maybe about the same weight depending on which version of K1000 and which version viewfinder on the LX.
The MX is an upgrade as far as metering cel, largest viewfinder among all (regardless of brand) fixed prism manual SLRs and has motor and film back options.
The ME Super has aperture priority.
The Ricoh XR7 has aperture priority and conventional control layout. Here is an ad for it.
The LX has TTL flash, aperture priority, interchangeable viewfinders and has sync to top shutter speed + bulb mode, available when batteries die.