Yeah, it certainly could have been better. I believe the original plans were for both the booster and orbiter to essentially be planes able to land on a runway. It's really a pretty awesome design, I mean can you imagine if we had a fully reusable launch vehicle in the 90s?

But the truth is, the shuttle was never really reusable, it was more like... refurbishable. It took a lot of maintenance for the heat shield and the engines after every launch. It was also amazingly complex, there were so many possible failure states, and in many of those scenarios there was just no hope for the crew. With a shuttle and with the future starship, we'll be seriously missing the launch escape system seen in traditional crew capsules. On some level, the last thing I would want would be to lose a whole shuttle crew and two booster pilots. (Though admittedly, these days the booster would certainly be unscrewed). I do also wonder, how much potential payload mass they'd lose by adding all the additional parts they would need to make the booster a landable aircraft.

Anyway, it is possible NASA could do that again, but it would be a serious investment to get that working, and right now I think they just aren't set up to take on a project of that complexity. Also, it would definitely distract and redirect funds from their ongoing science missions.

So yeah, they could, it would be cool, but I don't think it's a good idea.