I put stopping ability ahead of everything, myself, but that's just me.
That plug boot doesn't look like it's sitting right to me either... at a guess, it looks like someone's had the cylinder head off and put it back on turned 90 degrees.. Not sure if that matters, but if the head gasket isn't doing a great job you won't have good compression.
I'd check the plug wire, that one looks like it's being held taught when connected.. there could be stress issues at the boot or CDI end of it making for poor conductivity. Next up would be checking for power out of the magneto.
It could just be stubborn, too, as you have no idea what it's previous owner did or didn't do or how many miles it's had. Of the two bikes I have, one is nicely broken in and starts in a heartbeat, the other hasn't been out very often (maybe a half tank of break in mix so far) and sometimes I have take it to the top of the lane and roll all the way down to the house to get it to catch.