I dont know all the frame data from doa5u, because i dont own the game yet, but at least in doa5 tina`s jab was 11f and her fastest, non BT mid 13f. She is a grappler, as well, even more throw focused than rachel.
If your fastest attack is an 11f high, then I would consider that to be slow.
From what I hear Rachel makes up for that with frame advantage off of gb and lows? Tina has nice crushes to compensate.
It sounds like the best way to beat her is rush her down and not let her breathe, which is difficult with a slow character like leon, bayman, bass, tina etc etc. So I guess just counterpick her with Kasumi/Christie?