I never had any serious concern about ash until a few months ago, when I began using -- for the first time -- a stove that is exclusively front-loading. Prior to that, I have had LOTS of experience with open fireplaces, top-loading and side-loading stoves, and stoves that are front-loading but have elongated "cigar-burn" fireboxes. Some had ash grates and ash pans, some did not. But I never knew ash as a "problem" until now.
First, there is the ash that comes with reloading. With side and top loading, there was NEVER any ash spill; you open the door and put wood in, period. Now, every reload has at least some ash spill out just by virtue of the fact that it collects in small amounts on the inside of the front door, and drops on the ash lip when you open the door. Consider that a side or top loading stove would potentially have NO NEED for a functional front ash lip, ever!
Secondly, there is the issue of ash removal. Most stoves have a baffle system that results in air being pulled to the front of the stove, then up and back. When you open the front door, ash naturally spills out as a result of this air flow. Opening the side door does NOT result in the same sort of spill; on the contrary, air tend to flow INWARD upon opening the side door. And a top-loading stove of course has no such baffle system. (When you stir a pile of ash, the finer particles are going to disperse laterally more than vertically... so thanks to gravity, not too much ash spilled out of my top-loading stove.)
I find with my new stove that shuffling around the coals to get ash to fall through the grate results in ash coming out the front door, whereas it did NOT come out my side doors and top doors in any significant amount when doing the same thing. So my conclusion is that the ash pan OR ash plug system on many front-loading stoves is going to be "stupid" because it's not going to be much of an improvement over just shoveling out the stove, with some associated spill. The ash pans on my top and side-loading stoves, however, were very helpful, as they allowed ash removal with little or no ash entering the living space.
Top-loaders beat side-loaders beat front-loaders, at least as far as ash problems go.