Weapon failure at a fixed 2% has some interesting implications.
It's inconsequential on things like box launchers and large-calibre/low-tech beams.
Compactness becomes expensive in combat: half the weapons with twice the RoF will suffer twice the wear and tear.
Generally, cost-effectiveness for a given role becomes more important than overall capability; I see the biggest implication for point defence.
Long-ranged area defence features sophisticated weapons and low chances to hit, this may become much less viable.
Lower-tech final fire PD than available doesn't only save a few BP, it greatly conserves MSP in operation.
Generally, overengineered solutions become much more of a liability. Some restraint is encouraged rather than building the most sophisticated weapons available, with the obvoius implications on research priorities.
Some things (failure rate, weapon cost scaling with tech) may need looking at and testing, but on the whole I like the concept. It should make beam fights less one-sided.