Q: X doll just got a login SPEQ, does it make them good?

A: No.

Slightly longer explanation: no login SPEQ substantially changes the role, or performance within the role, of a given doll. The SPEQs tend to have marginally better stats than standard equipment, and offer a minor enhancement to their skill. Most dolls are far more than a minor enhancement away from being viable. If you like using the doll, they'll be slightly better. But that's it. Notable half-exceptions:

• Grizzly's mobility skeleton gives her a bit of an edge over generic buffing HGs as it adds a "free" 8% ROF. Note that Grizzly was already a good buffing HG, and she still doesn't do things like what P22/Kolibri/Webley offer.
• 9A-91's high-performance chip is relatively impressive, making her preferable over OTs-14 as a night AR. But she's still a selfbuffing night AR, which aren't really needed for anything, and she offers no extra utility like AS Val mod.