The only problem I see is that TP generation in FFXIV is several magnitudes faster than in FFXI. In FFXI it generally takes at least 30 seconds to gain enough TP for a WS, while in FFXIV you just pop Invigorate, then do a couple TP builders and you have enough to spam three TP moves back to back, soon followed by a fourth.

One option would be to have only certain abilities be chainable (perhaps only 2k+ TP abilities?), but I'm not sure how to implement it without making everything seem unnecessarily convoluted.

Something definitely has to be done, though. The BR system has been improved since launch but it is fundamentally flawed in its design and has to go. Even if we ignore its poor functionality, it is also much less exciting than the skillchain system of FFXI.