I have once suggested the splitting ( but keeping total number of sub-forums at the present number of 5 or so).
However, if splitting is not considered an option ( as we have seen before ), I like the " new thread with a link to the earlier one" suggestion. That keeps the option for "archaeological scavengers" to look at old stuff, while at the same time leaving others the freedom to move on at the right speed.
just my 2 ¢