Flags spawn when at 3:30 if there is only horse ranged left, which is a long time. Mostly rounds effectively end before even reaching 4:30, with one team emerging victorious and just having to chase down a few scattered survivors. Which means that a horse archer usually has like a full minute until the flag pops up, then people have to move to the flag and then they have to raise it. All in all this usually allows horse ranged to delay for 2 minutes at least while the fighting part of the round lasted like 2-3 minutes. That is way too much in my opinion.
I always go for flags immediately simply to not give the horse archer the satisfaction of being chased, let him be a delaying shithead and demonstrate how futile his delaying is when he loses by flags, but not everyone does. People usually ignore flags because they want to get the lucky kill, which only allows delaying by horse archers to be viable for valour attempts. Flags are slow and ineffective.
I am all for desperate solutions as making horse ranged missiles do 0 damage when facing more than 6 opponents similar to what the Mercenaries mod had. They can play their class when everybody is else is able to play theirs, not when they are egotripping while 60 people are watching them prolong the round by a 100%. In any case though, remove the minimal wait time for flags at 3:30 and make them pop whenever only cav is alive on one team.