The roadtec is a flatter profiled tyre, in effect a Pirelli Angel. My mate just wore a pair out on his Tracer 09 and they wore only slightly better than the 7RR. They are also a more comfortable tyre than the 7RR if you don't like the constant road telemetry of the sportier tyre. He is swapping out to a pair of RS3s because he got a great deal on a pair-though, he was close to buying the 7RRs because of the 2:1 fronts to rears.
Big improvements are very difficult these days. It really comes down to the riders/motorcycle profile preference. Sports touring/sports rubber have now almost aligned in performance terms with the higher miles, more comfortable tourer end giving very little in performance terms against the sportier end. Likewise the sportier tyres give up little in cold/wet grip/wear to the tourer end but give only a modest improvement in stability/ feel.
I wouldn't get too hung up on the differences between the roadtec/pr4/dr3 as they pretty much perform identically. The differences are only in the profile feel, nothing else substantive. As long as the tyre gives you confidence, then any are as good as the other. Indeed the older PR2 is almost as good as the PR4, as the RS1 is to the 3. Even the evergreen 023 shouldn't be neglected-it's a higher mileage tyre with a sportier profile that manages more miles without losing its shape whilst losing only marginally in damp grip (the trade off is that it feels less secure on alternating damp/wet, but actually gives a massive margin of feel over its actual grip-in other words you get bags of warning that grip is marginal without getting anywhere near the point).