Basically three disadvantages, 1, most of them are not ambidextrous viz the the ejection port location. 2, they are louder, because the action is nearer your ear. 3, most require more hand movements to change mags; not a good thing in a firefight. Against this are the advantages; more compact, higher muzzle velocity, better for going prone, generally modern components & design
The fact that quite a few bull pups are somewhat louder for the user and (more critically) not as quick to reload affect their combat utility, which is a bit more important than personal preference. Of course other weapons have disadvantages too; bullpups are not alone in offering plusses and minuses. Some of aspects are irrelevant for airsoft; a bullpup airsoft is not going to have a higher muzzle velocity, but nor does it eject shells, so actually IS ambidextrous, although blowbacks might s...
Ease of mag changing with bullpups is relevant for MILSIM airsofters using realistic mags though, but not really a big deal for high cap mag users. It is simply a lot quicker to change mags on a weapon where you can release the mag with your right fingers, i.e. like on the M4 and the AK, since it drops the mag leaving your left hand free to grab a fresh one and get it in place quickly (even whilst still firing your last few rounds if necessary). Then again, the AK has the charging handle on t...
Then again, the AK has the charging handle on the 'wrong' side and the mag is appalling for lying prone, whereas the M4 has the charging handle better placed and the mag is better for going prone, then again, the AK has a better fire selector design than the M4 and is less prone to jamming, so these 'classics' are not without their faults either.
Theres always going to be tradeoffs so really its up to the player. In regards to reloading quickly, here someone does as you described with a bullpup
I think reloading quickly depends on the individual gun more than the style, like how you have compared Ak's and M4's. And yes a lot of the points are made irrelevent in airsoft like shell ejection. I personally prefer a compact gun, and I don't think I'm put at a disadvantage in a gam...
everything we own is done to our own preference, sometimes it is nice to not follow the heard and dare to be different. I wanted a L85 & AK - simply coz I wanted one but mainly stick to M4 - not coz M4 is better but it is what I prefer to use as all rounder - yet AK is longer barrel & bigger mag and can have edge over M4
& L85 has longer barrel - not the be all n end all but uses same M4 mags & is Blitish made in Hong Kong but patriotic maybe & different to most others - like them all but use M4 the most
Being super lanky I found the trigger was too far back on the AR style rifles even with the stock extended out (this was on the rifle I borrowed for my first game) Bullpups wind for me there.