triforce has never been cost inefficient and will never be cost inefficient unless it is raised to 5000-5400 gold and even then i'd still buy it on a few characters
its stat distribution is basically a flat base upgrade to almost every single character stat and the extra 50% on spellblade proc and phage slow merged into one item makes it a fantastic buy on just about anyone. iceborn is nice, but much better on characters that can utilize the extra stats (gauntlet on malphite is a terrifying thing). don't be tricked into thinking the field slow deals damage when the field is initially placed - it doesn't, a lot of people seem to think it does
ezreal's escape is a small factor in what makes him so good, tbh. his passive is EXTREMELY good for an AD, possibly the best passive of all the AD carries since a 45% attack speed increase is a massive dps increase which can be maintained with very little effort on his part over the course of a teamfight. it's a natural flat power bonus to him that makes every purchase of AD on him worth more by default simply because he can use it better. couple this with essence flux still imparting a fairly potent slow, a free flash every 16 seconds, a global ultimate and a 1.55x attack range poke/farming ability and you get one of the most well-rounded attack skillsets that league has to offer
and to compensate for that he has mediocre base health and poor resist scaling - something shared with every other AD carry
AD ezreal has never been a poor pick even in the depths of his nerfs way back when, he was just a lot harder to pick up then. with the new itemization offering even greater offensive polarisation on him, he's super-viable now and they'd literally have to chuck a rengar on him to drop him down to a reasonable level. so they wont and instead will likely bring other AD carries up to his level with small changes as they have been doing
its stat distribution is basically a flat base upgrade to almost every single character stat and the extra 50% on spellblade proc and phage slow merged into one item makes it a fantastic buy on just about anyone. iceborn is nice, but much better on characters that can utilize the extra stats (gauntlet on malphite is a terrifying thing). don't be tricked into thinking the field slow deals damage when the field is initially placed - it doesn't, a lot of people seem to think it does
ezreal's escape is a small factor in what makes him so good, tbh. his passive is EXTREMELY good for an AD, possibly the best passive of all the AD carries since a 45% attack speed increase is a massive dps increase which can be maintained with very little effort on his part over the course of a teamfight. it's a natural flat power bonus to him that makes every purchase of AD on him worth more by default simply because he can use it better. couple this with essence flux still imparting a fairly potent slow, a free flash every 16 seconds, a global ultimate and a 1.55x attack range poke/farming ability and you get one of the most well-rounded attack skillsets that league has to offer
and to compensate for that he has mediocre base health and poor resist scaling - something shared with every other AD carry
AD ezreal has never been a poor pick even in the depths of his nerfs way back when, he was just a lot harder to pick up then. with the new itemization offering even greater offensive polarisation on him, he's super-viable now and they'd literally have to chuck a rengar on him to drop him down to a reasonable level. so they wont and instead will likely bring other AD carries up to his level with small changes as they have been doing