Sorry but gotta disagree quite hard on this one.
First of the notion that the maps are not designed with 24 second timers in mind doesn’t hold.
Sure maybe the first iteration wasn’t, but since they have symetrical timers they clearly balanced the maps for it. The objectives and the spawns are placed exactly so that both teams roughly reach them at the same time, with a slight advantage for the defenders, to you know setup a defense, for the attackers to overcome.
If the Echo data indicates that the balancing is not right, SD usually shifts spawns around to help the weaker team just so slightly, which is easy to do since symetrical spawntimers.
Randomness now normaly I’m the guy who defends randomness as a tool to make things more interesting, but this time…
Asymetrical timers are just as easy to predict as a symetrical ones. Atleast at comp level play. Only difference is with symetrical you can look at the ingame timer, with asymetrical you set an external tool (interval timer, there is an app for that) to the enemy spawntime hit go at start and you are set. Only way to prevent that, is by having a random variance to it (spawntimes +/- 5 for example) but that could be done to symetrical timers aswell.
Symetrical timer ensure that spawnwaves always clash at roughly the same time/point. Ensuring that the fight is always around the point of intrest (objective, unless ofcourse one team is considerable stronger and survives wave after wave).
Asymetrical, in contrast means the one with a shorter timer (presumable offence) will cover more ground pressing the enemy out of position after an even trade.
Symetrical timers give the same risk/reward treatment for everyone involved in a fight.
You can do a save attack, that will put you on a short spawn when you loose, but the gain is low, since if you win, the enemy gets a short spawn aswell. Likewise if you do a high risk attack you might put someone into a longspawn, but if you fuck it up you get punished with the same. Adding a low risk/low reward, high risk/ high reward component to firefights.
Asymetrical on the other hand, because the spawntimes are drifting against each other, mean that you will have situations, where you have low risk/ high reward and high risk/low reward situation (on top of everything else).
This is quite important because it generates situations where one team can suicide charge in. Force the other side into longspawns and show up early, because all their loses imidently respawn.
I’m not saying that Asymetrical couldn’t be done. And it obviously has been done, in the past. But it would generate quite a few atleast in my eye undesirable situations and introduce a whole new set of variables, that would need a large round of rebalancing, since bringing it back to the first part. Everything in this game is balanced with the current spawnsystem in mind, wether its spawn points, mapflow, movementspeed, cooldowns, plant/defuse/repair times.