with this nerf irelia is pretty unplayable, irelia ult is pretty weak but was good because of low cooldown, now is not; compare with other ult
IRELIA: per blade 80 / 120 / 160 (+ 50% AP) (+ 60% bonus AD) TOTAL DAMAGE:320/480/ 640 (+200%AP = 0)(+240% bonus ad) cd: 110/85/60
DARIUS: MAXIMUM TRUE DAMAGE: 200 / 400 / 600 (+ 150% bonus AD) COOLDOWN: 120 / 100 / 80 = pretty same cd but deal true damage and has a reset, plus is a single target so you can't miss while you can miss irelia's blade
CHO'GATH: TRUE DAMAGE: 300 / 475 / 650 (+ 70% AP) cd 80 same, true damage single target unmissable, lower cd.
EKKO: ult does lower damage but can be used as disengage and heal ekko, same cd, but is better than irelia ult, practicaly ekko can't lose 1v1 in lane vs irelia
MALZHAR: TOTAL MAGIC DAMAGE: 25 / 35 / 45% (+ 7.5% per 100 AP) of the target's maximum health, CD: 120/100/80, whaat we are talking about? same cd, but is a 2.5 second suppress and oneshot
WARWICK: same as malzhar, suppress, oneshot and same cd as irelia ult
OLAF: cd 100/90/80 his ult buff him for 1v1, lower cd than irelia ult, so irelia can't trade with him in lane
FIORA: same cd as irelia ult, but more damage and more heal
if we compare irelia ult with tank/engage ult is the same, irelia ult with so high cd is weaker than all ult
hard engage ult like: malphite does pretty same damage but has hard cc and only +20 sec cd; sejuani is the same little higher cd but more usefull ult
long story short: irelia ult with this cd is useless in lane and in teamfight, in teamfight ult only does not high damage but no cc, in lane has same cd of more stronger ult. Plus you nerfed irelia after trinity change, so now trinity is mandatory: if someone wants to start with difensive item (malmortius or some armor item) because he is behind, he'll go more behind without trinity
now downvote me without reply, that's how it works