Actually, it's not only the D70 that omits this feature. All Nikon entry-to-mid-level AF SLRs cannot meter with manual-focus lenses: F65, F80, F60, F50, F55, F75, and even the D100 (as well as the Fuji S1 and S2 pro, Kodak 14n.) However, they can still be used in manual mode with MF lenses, with an external light meter or your judgement, of course. That should not be as big a problem with the DSLRs.
Nikon took that route more from a business perspective than a technical one. If you bought one of those SLRs, you'd have to buy new lenses for it instead of hunting for older lenses on the used market or using your existing old lenses, thus keeping Nikon in business! It's the lenses that are the money generator.
Pentax have been more generous in this regard: You can still use Pentax SMC lenses dating back to 1975 (when the K-mount was introduced) and any other K lens on modern entry-level SLRs like the ZX-L, but they seem to be doing like Nikon did with their new *ist/D line!
Some people call it progress.
Shady