Need an upgrade from Pentax K1000-- metal body 35mm camera with hotshoe... and k1000 vs. "better" cameras?

I'd like to get a classic metal-body 35mm camera to replace my Pentax k1000... I have been shooting digital for awhile and when I shoot film, I almost exclusively use medium format cameras, so unfortunately I have little knowledge of what 35mm camera would be a good buy for a serious photographer on a budget. It has to have a hot shoe for a flash, as well.
Also, I know the K1000 is marketed as a beginner's camera. Why is that, exactly? What makes it different from similar-looking 35mms that aren't "perfect for amateurs"?

The K1000 "is" a classic metal-bodied 35mm camera.

It has a hot shoe for a flash right on top of it.

Unless you don't like the lenses, there's no reason to trade it away.

It's thought of as a student's camera because it has manual controls (which instructors want) and it's cheap enough for students to afford.

All manual-exposure, manual focus 35mm cameras will be virtually identical to the K except for the name plate.

V

If you have been using medium format cameras, I don't see a problem of transferring you photographic skills to 35mm .. You may want to buy a good used Nikon or Canon 35mm SLR, since they are not only the ones pro photographers use, but also have the most complete camera systems. When you eventually start shooting using DSLR's all the lenses made by Nikon since 1959 and all the ones made by Canon since the advent of the EOS system (1985) will work on the new (and old) cameras