In guys on TRT the amount of aromatization has a trivial effect on testosterone levels. Estradiol is only running around 0.4% of total T. Furthermore, each 1 ng/dL of testosterone converts to 10 pg/mL of estradiol. So you can have have sky-high estradiol of 100 pg/mL and it only took 10 ng/dL of testosterone to get there.
It's a different story when your HPTA is working. Basically, testosterone production is regulated to achieve a fixed level of free estradiol. If the rate of aromatization decreases, such as through an aromatase inhibitor, then testosterone production is increased to maintain that desired level of free estradiol. So yes, you do get more free testosterone.
A speculative concern about aromatase inhibitors is the effect they have locally; that is, aromatase exists in areas such as the brain and vasculature. Is it possible that AI use leads to lower levels at these production sites, starving these tissues, even though total serum levels may seem ok? I don't think we know for sure.
The research on testosterone and libido shows that if you have normal testosterone then higher levels do not lead to further improvements. There's anecdotal evidence that sudden increases in testosterone help, but only temporarily.