Personally I think indestructible ladders is worse than destructible, because it pretty much eliminates any chance of using tactics with your trap placement. The ladders often appear in locations where it's difficult or impossible to place traps effectively. The ladder destruction is essentially a mini-game within the game, but the difficulty comes not from challenging game mechanics, but from lack of AI and a clunky interface, making it tedious and frustrating instead of fun.
For whatever reason, the minions don't attack the ladders unless you direct them to. That's the biggest flaw with ladders, eliminating that would really go a long way toward reducing the frustration people have with this.
The problem is, targeting the ladders to make a unit attack them is problematic, because in management mode, you can't click on the ladder if there's a unit next to it, as the icon covers the ladder. So you have to zoom in close to click on it. But then you have to zoom back out to find the other ladders. Even when there's not a unit near the ladder, targeting the ladders is inconsistent and unreliable. Annoying and not really fun.
Here is a method you can use to take out ladders entirely from the management view, without having to zoom in or out. As soon as you hear the new ladders announcement:
* Zoom out to management mode and pick your first ladder.
* Right click a little ways away from the first ladder you see and teleport a high DPS squad there. Don't put it too close, or the circle icon for the squad will cover up the ladder. They should be far enough away that they have to walk a little to get to the ladder.
* Mouse over the ladder, watch for the cursor to change to the attack symbol (sword). This is the most important part, practice this until you're sure you can target the ladder consistently. If you have trouble keeping the ladder targeted, try reducing the mouse sensitivity.
* The squad you just teleported is automatically selected, so you don't need to click on it first.
* Wait just a moment to be sure you've got the ladder highlighted, then right click to make that squad attack the ladder. Since they're not right next to it they will have to walk a short distance, but that's ok.
* Immediately pick a second ladder and teleport another high DPS squad to that one, repeat the process above.
* By now the first ladder is down, so locate the third ladder, and repeat the process with the same squad you used for the first ladder. Alternate between the two squads until all ladders are down.
Things to keep in mind:
If you want you can use more squads, or even Baal himself, but the important thing is to have a plan and stick to it, don't change your mind partway through. If you ALWAYS start with squad 1, then 2, you don't have to think.
If you click too early, the squad may not attack, so don't try to attack the ladder the instant the teleported squad arrives, wait a moment first. Or maybe try right-clicking twice instead of once.
If you miss-click one, don't go back and try to fix it, go on to the next ladder, then jump back to check on the one you messed up on.
Sometimes two ladders will appear right next to each other. Don't bother trying to get the same squad to attack both, just teleport another squad in from the other side. Sometimes the same squad will attack the second ladder without prompting, but don't count on that, I've only seen it happen occasionally.
One thing I sometimes do is deliberately destroy only those ladders that are not in good position to place traps around. It allows me to reclaim a little bit of the strategy element that this mechanic screwed up.
