You don't need to ask, I'm content to correct nonsense when it might otherwise misinform divers looking for good advice on the forum.
If YOU have a problem with drysuit trim and dumping, then I suggest you look for a solution. But generalising YOUR problem into some sort of common fault is.. well, it's just some sort of self-denial mechanism.
If a diver
needs to drop trim to vent their drysuit, or has to rely on a top-located LPI, then there is some sort of foundational weakness in their skillset.
I'm not a salesman for XDeep, but I do feel obliged to correct ridiculous statements made about decent gear. I was writing articles on sidemount design heritage and have been consulting to sidemount manufacturers for many years. There some really great rigs on the market nowadays, XDeep is just one of them.
2004 called and wants it's top-mounted inflators back...
XDeep is a Polish company.... as far as my geography goes... that's not a warm-water, wetsuit diving nation?!? Their kit was proven in ice-cold mine and cave diving. Do an image search and there's
many more pictures of drysuit clad divers in XDeep than wetsuit. It's used by some very credible, field-leading divers.
I dive a variety of rigs and don't have any big preferences when it comes to recommendations. I've merely iterated that it's wise to select a rig that suits your needs.
I get the impression that you've got very little, if any, real experience diving some of the rigs your 'talking fact' about. It shows....
The latest generations of sidemount rig are transcending the old steel/aluminium optimization divide. The
XDeep Stealth Tec, DiveRite Nomad LS,
Apeks WSX25/45, Hollis Katana ... . all those current-generation BCDs are much more unilateral and effective whatever tank choice you prefer.
I won't really comment on the German sidemount scene.... my only observations on it are yourself,
Razoristia and some hilarious viral pics of people churning around in ill-modified BP&W 'rigs' having a taco'ed-wing frenzy.
It seems a quite insular and very out-of-touch with regards high level, global sidemount usage and trends. I'm sure I'm wrong... but I just don't see German sidemount diving represented well here on Scubaboard.