Missed the part about pouring concrete I would not be concerned at all about the imperfect joints either . OP was though making me wonder what problem with the joints were
No real problem with the joints (no big gouges or burs), just an approximate 1/4 gap between pipes under the fernco fittings and the cuts not perfectly square but not bad either.
I was just thinking theoretically/generally how this unsmooth new part of the drain system would not catch debris.
Also, does a toilet with more 'flushing power' help to clear out the lines immediately downstream better (shoot more volume of water faster down through the drain)? I assume this is the obvious case.
Or are they just better at cleaning out what is in the bowl?