Talim IS low... and until Namco either gives her more range, or stops making her at such disadvantage, she will probably stay that way... There are several reasons to why she is low tier...
1. No range. I mean REALLY no range. Not like Taki that looks like she has no range, but then she actually does, Talim actually has no range. A lot of characters with small weapons will push forward when they attack, giving them deceptively long range, but Talim doesn't.
2. Very punishable. The majority of Talim's moves are punishable, and if its not punishable, more than likely it is at disadvantage. She rarely gets advantage on hit, to the point when I actually do a setup for advantage, my opponents are amazed and end up eating minor counterhit damage... She has a lot of disadvantage on HIT.
3. Minor damage. Yes, as part of #2, when many characters get advantage, they use that oppurtunity to do pokes, which could be mixed up into higher damage setups. Unfortunately, Talim's pokes do so little damage, and her damaging moves are so slow and unsafe that the advantage often goes to waste.
4. Risk VS Reward. Most characters have these really slow moves that do high damage; but almost all of them are safe and often give advantage. With Talim however, her really slow moves are the unsafe ones. She has to put herself at major risk in order to get any sort of mediocre reward.
5. Interruptable Everywhere. If you're fighting against Talim, you should be attacking always. What? Talim is flying at you with arms akimbo? Just hit BB and yell out "FACE!" All of her stance shifts are interruptable. She's jumping back? Well its not instant tech jump or instant backstep (like Raph's, X's or Yun's), just BB it.
6. SLOW. Talim SHOULD be a fast character; but she is not. When she attacks, she puts herself out first before her weapons (hence why she is interruptable everywhere).
7. Lack of TC. Yes, Talim rarely tech crouches anymore. To the point where she really only has ONE tech crouch low (WC A+K). Almost all other characters tech crouch more than she does; and they do it all the time. I find it very hard to do a simple AA because everyone is always tech crouching.
8. No Auto-GI. Everytime you go into back stance, you are at disadvantage. Period. Without the Auto-GI, you're gonna get hit, just take your licks and move on.