The reason TeX is still used is because it is open source and beautiful, because it is the best at handling mathematical notation, and because of its inertial dominance in math and the hard sciences in Academia. The reason TeX has so, so many fixable problems after 30 years is because there is no financial incentive for anyone to fix it. The answer is not to find a TeX alternative. This will not be possible in Academ…
The features you mention would be needed to put it in front of less geeky users but are far from the core issues. I'd love to see a language with better flow control and abstraction features put on top of the Tex engine that indeed produces beautiful output. Maybe LuaTex will be that.