Why is hakkapelit so broken

Sweden definitely doesn’t need something like a Rifle Rider. They can use their artillery to deal with heavy infantry. The skirmisher function they are missing is countering light cavalry. That’s probably what they were trying to do with giving Hakkapelits a bonus versus all cavalry in melee, but what they’ve made is obviously too powerful. Their musk-goon unit also falls short in some matchups like against Rifle Riders so having Hakkapelits as anti-heavy cav is hugely beneficial in that matchup. A primitive skirmisher unit such as a European Arquebusier that specializes in countering light cavalry is more what Sweden needs to cover its shortcomings.