IMO/E, it seems that certain companies like your profile or not.
Ex, I have 2 Citibank cards (BB and ATT) and neither have very high limits. While I did just get auto-CLI from them, this was the first time in years. Neither would budge when I called about an APR reduction.
On the other hand, while Chase wouldnt do much with my Slate card, I did get a Freedom card at a much lower APR and more than twice the SL. Was able to move the CL from one to the other with a simple call. Discover has moved us up steadily with auto-CLI's.
Its really up to you - would you use it enough with a higher limit to justify the HP?