When I switched away from the 6.1 Classics, I wanted something with more flex and baseline control. The Volkl C10 was an easy transition for me at the time - instant boost in baseline consistency and the overall package had a similar weight and balance as my 6.1's. I can also say that compared with some other 98" frames I've used through recent years, the C10 gives me the impression of a racquet that's a little less clunky like a 95". It might be the somewhat narrow beam - not sure.
I also re-tooled my ground strokes when I made that racquet switch - including my re-learning a solid one-handed backhand - and the comfort of the C10 strung with a snug bed of syn. gut has been wonderfully easy on my arm. This frame gives me all the power I could want, but it's not quite as spin-friendly as a couple of other rigs I've used. It's a decent alternative to the 6.1 Classic, but it does have its own personality.
I also agree with the recommendation of the 95" Yonex models you might find. If I were to go looking for new racquets from that brand, those are the first ones I'd try. I've had a couple of outings with the RF 97 and I suppose that this frame is something of a modern update to the 6.1 Classics. Because the RF 97 was a bit similar to the 6.1 Classic, it wasn't for me, but it did have "that personality" of solid heft, head-light balance, and decent pop. Easy to hit the ball with some zip (including serves), great for serve and volley action, but a bit too unpredictable for me around the baseline.
You might want to also check out the Volkl V-Sense 10 Mid. I haven't played this one myself, but it looks like something that's rather close to the layout of the 6.1 Classic (96" Volkl hoop is close to the 95" 6.1) with a little less weight. That's not a big deal to adjust yourself with some lead tape and a little home tuning. I've had great success with dialing in a couple of racquets myself in recent years. Nobody is producing frames that are very close to the 6.1 Classic in terms of weight, balance, etc., but I think that a little tuning can often get a lighter racquet closer to that familiar design.
I also had a quick sampling with the Prince TT 95 a couple summers back. That's another frame with a layout in the neighborhood of the 6.1 Classic, but the TT 95 is also a bit less hefty and offers a little extra flex.
