I got bored so I'm gonna stoke the flames on this argument I see all the time. Please keep in mind I am a bronze-ish level player that has enough "game knowledge" to not fall into iron but bad enough aim to not make it to silver.

Reason 1: The maps are very big

Not only are Breeze and Icebox incredibly big in terms of raw size, but they also have incredibly long peeking angles and generally large/open sites compared to other pre-icebox maps. This has a couple of effects. Short-range guns like shotguns and the stinger have a horrible time on these maps when there are only 1 or 2 areas where they're in their effective range. Longer-range guns like snipers and the vandal on the other hand thrive in most situations since it's much harder to rush them down unless you're Jett or Raze. Out of the 17 guns, (including pistols) I'd say only 8 of those guns are viable most of the time on Icebox/Breeze (if you're curious I think only Phantom, Vandal, Op, Spectre, Sheriff, Ghost, Guardian, and Marshall work, yet another thing to argue about).

Speaking of Jett, these maps cut the number of viable characters also in half. Cypher and Killjoy are nearly useless, with Sage barely getting a little use out of certain wall spots. Omen and Brim are usually bad picks, with Astra and Viper being the better smokers. Breach suffers horrifically and Sova/Kayo start getting bad on Breeze, while Skye is busy popping off. Raze and Phoenix sort of hold on in Icebox, but their usefulness drops off on Breeze. Yoru doesn't really matter since he's just not very good in general, Reyna is all-around good for anywhere (though if you're holding a really long angle her flash falloff can actually come into play on Breeze). And of course, Jett holds on as being the best duelist pick no matter where you are. Having only half of the roster work on a map is incredibly limiting and makes the map get old quickly.

Reason 2: They encourage the same plays

When you only have certain characters and guns work on a map, the meta for it is established quickly and usually sticks. Viper cuts off half the site and goes back to spawn for lineups, Skye flashes in, Reyna baits the Skye, Jett does some dumb shit with her knives, and Astra goes afk in astral form to support the viper lineups. While that's a little bit of an overdramatization, it still holds some truth. With mid being a death trap for both maps, only one reliable entrance onto site (fuck the door on breeze), plays are held back and restricted to a few basic plays if they don't want to get immediately op'd by the top fragging Jett on the other team. And that's just for attackers. Defenders have a horrible time deciding whether or not to rotate, and with Cypher/Killjoy being bad you don't have reliable autonomous information gathering. And if your anchor dies, good luck retaking a site that the attackers essentially took for free and had 10 minutes to set up on.

This is a little bit of a personal gripe, but these maps also make flanking incredibly easy and deadly. I understand that flanking is an important part of crippling a push but when you got shot from your spawn while you're in the middle of mid it gets old fast. Fracture also can have this problem but at least there are safe places to hold/hide in and flanking is expected due to the double sided attacker spawns. Defender flanking on the other hand is incredibly difficult to pull off, as you're mostly limited to one area to flank throught that's usually pretty close to the default plant spots, meaning that Viper doing lineups will spot you.

Conclusion:

I don't necessarily hate the maps themselves and this wasn't meant to be a degredation of some sleep-deprived Riot games dev who just wanted to finish the map and go home. I think the maps have some cool things you can do with them, but the amount of lame/boring things that happen just make it a little hard to brighten up when you see the ice/beach pop up in the queue. Anyway, thanks for reading I guess.