Removing the armor on Tonfa Strike would make the move useless, the only difference you'd get from it is that the second rekka becomes -4 opposed to -13 (gapless), it's just not worth the bar given what she can do with them. Either way, 8% for a safe armored move is not an issue imo.
Changing the mid to high removes the ability to hitconfirm when you catch your opponent pressing buttons (and thus any damage potential), which is pretty much how she has to be played, like Dragon said, she'll be playing more like Tremor but Tremor has a +11 on block Rock Drop (that he can combo off and punish opponents who try to steal pressure) to special cancel with his d1/d4, Tanya just doesn't have the meterless tools for poke mindgames and with Rekka's being most likely nerfed, that leaves little options for a character that has holes everywhere. She basically won't be doing much pressure up-close and that's where her (Kobu's) strength is.
About your other points, yeah I agree, she shouldn't be plus but maybe around -4 (fully delayed) if Liu is not building meter in his pressure, I don't mind seeing Tanya have something similar, as long as rekka's don't become absolutely useless, because it's always been a risk using them.