Being a sneaky ninja trying to pull an epic portal to the inner wall of Bay or Hills or just to solo the lords was a such appealing play style for some of us, and this marked stuff just makes it impossible to do it again properly like the ol’ good way. In my opinion just leaving a player searching for rats did the job perfectly and allowed enjoying WvW in a completely different way.
My improvement would be that the marked debuff won’t be applied if a player is stealthed at the right moment the enemy captures the structure.
(That’s my very first post so I don’t know which are the format rules, plus English is not my mother tongue. Sorry for any inconvenience.)