Too exploitable in two ways:

First failure mode is that the metric for two bills being “the same” will be too narrow, in which case the rule will be ineffective due to legislators playing with the punctuation or paragraph structure, or

Second failure mode is that the rule will be too broad and this becomes a weapon which would increase gridlock even further.

By providing parties and non-majority fringe groups within them the option to “damn bills by weak praise” into the future, legislators working adversarially could propose a bill they don’t want to pass, veto it, argue any successor bills are “the same bill”, and now, they’ve effectively enshrined the state of the issue for the next X years.