Been a while since I had adsl so its hard to remember what made for good or bad stats, but I'd say error rates are really low for the line length.
~ 50 FECs per minute on the downstream, 0 CRCs. ~30 upstream CRCs in 12 hours is I assume well within DLM limits even on ADSL.
1.6db downstream margin, if you believe the previous modems were maybe cutting it even closer you could drop this down to say 1db to test. Graphs of downstream SNR margin over a the course of a few days would really help to see if you had any room there. It might be rock solid 1.6db all day and night, it might vary considerably, knowing where it bottoms out would tell you if could get away with lowering it slightly.
Similarly knowing when you had the highest margin would allow you to pick the best time for a resync, but thats pretty much equivalent to changing the margin yourself with the method discussed elsewhere.
16ms of extra delay due to interleaving might annoy someone who plays games, but given your line length seems a small price to pay given the low error rates.
Is it well documented that broadcom's phyre works on ADSL2? I have no memory of it from my line. Good that it seems to enabled and doing its job though.