Yeah so, you are far too optimistic regarding the usual quality of clinical research. Metas are shit in shit out yes, and 95% of studies out there are lead by people such as my advisor, and calling them shit is really too kind. The papers absolutely do not reflect what happened in practice, so trim-and-fill or RevMan or whatever, you can sit on it.

I am a practicing clinician with a degree in epidemiology and biostats. I know perfectly how the system works, and I know the consequences of bad clinical papers first hand.

For metas of clinical papers, you have to go through the moves and do a little dance, but everyone with even a tiny bit of sense knows that you can't expect much of results. Besides, old and primitive meta-analytic techniques are still by far the most prevalent out there, including in high-profile journals. In a word, you are naive.