Bob,
Yes, the AO-10/AO-13/AO-40 days "were the days" for DX. But so were the 1970s and pre-AO-10 1980s, when a lot of us were working DX on AO-6, AO-7, FO-12 and the RS birds. It was more challenging than HEO operating, but IMHO it was a lot of fun, and about a dozen of us made WAC and DXCC, all-LEO.
There was some SSB, but most LEO DXing was on CW. We used all satellite modes, of course, but more DX was worked on Mode A than B or J. Mode A had a slightly better downlink range than B or J, if you had a good 10m beam and a low-noise QTH. For a discussion of that, see my QST article on the AO-5 propagation test results.
The good news is that AO-7 and FO-29 (successor to FO-12) are still with us, so we can still do it. Let the good times roll!
73 Ray W2RS