classic just didn't last long enough, kungen salty his epeen got chopped off because the game no longer caters to his niche playstyle, what a shame.
if they held back tbc for another 6 months to a year, way more guilds would have got to, and cleared naxx. I just remember there not being enough lockouts to gear ppl up, not enough raids in a year to progress unless you were making progress every week. if you didn't make progress, you fell behind. if you fell behind you didn't get to see the content before tbc came along. it wasn't harder, it just took longer, you got less gear per week spread over 40 ppl, we were running molten core just for ragnaros, everything was getting disenchanted, but ppl still wanted t2 legs. zg was being run for the enchant, in the end we were doing 1 molten core raid, 1 bwl raid and 1 optional 20 man raid for zg/aq20. what we should have been doing is raiding more days, we needed to be doing 1 mc raid for raggy, then making progress in bwl during that same raid, then having a whole raid dedicated to bwl, and adding an extra day in the week to progress more.
if classic had lasted another year i know my guild would have been able to progress to the end, perhaps we would have struggled a bit, although if we had time to phase out our mc/zg/aq20 raids, we would have made a lot more progress in bwl and been able to move into aq40 and eventually naxx. the only thing that stopped us doing so was time. we killed vael on our, 2nd or 3rd bwl raid, the boss that was apparently the 'guild destroyer' yeah, we didn't struggle on him. in fact razorgore took more attempts to get right than vael did for us.
in other words if you weren't raiding 4-6 days a week and making progress you didn't get to the end, that is all it was, difficulty wasn't what stopped ppl reaching the end, having to raid every day did.