arps. Well as easily you set up J37, a person who is experienced with his synth and arps will set it up, as fast too, in this simple form. The normal aprs arent retriggering the sound but are just gliding through different notes, also you can chose the length of the steps, which step to do particular stuff (glide to another note, or retrigger it), or randomize it (or the imput note order). Or you can chose the speed, arpeggio modes, bpm sync the speed or make it tempo based, control the shuffle, and many more misc stuff. Trust me, a simple arp command with total control of 2 is reeeealy primitive, there are so much more possibility.
And you can start saying: well sure, but i dont need anything more than those 2. I say, you shouldn't base other peoples needs and expectations on yours. We didnt started this night chat with personal demands, but with facts, about limited and primitive systems.
No, not it we're talking about channel volume here. If Mxx would just mean that all note volumes are multiplied by a factor, then it could be done in the same way with a vst. But if you assign several volume-controlled channels to the same vst, this is not possible, because a vst just has one master volume, whereas a sample has as many master volumes as there are channels.
We're talkin about the same stuff i think. We have routing possibilities here, so you can route 1 VSTi to many channels ("splitting" the sound if you like), much the same effect, as you would experience with the samples. And every channel has its own local volume mixer, so 1 played VSTi, routed to different volume based channels will sounds as loud or calm, as the routed channel are preset. I hope it's more clearer now, i have troubles sometimes, with explaining stuffs .

Also, you cannot simply turn off a synth's arpeggio as you can with Jxx (where you just don't write out the effect anymore) - ooooooooh right, you can automate it, but that's just a crappy workaround.
If you count LFOs as VSTs, well, ok, but using an LFO to control a VST parameter is not possible in OpenMPT.
Well good arguing point

. I think too, that you shouldnt blame the incompetence of OMPT, against the standardized MIDI/VST system.
LFOs are quite basic input forms on most vst hosts. Also turning on/off any VST fully, or internal controls (like arps) are archived with one simple x001 or x000 command (can be triggered from the pattern effect row too, dont even need to be automated). I really wouldnt call this "crappy workaround" neither, but a most natural thing to do. Dont need it anymore, bing, turn it off with an off command.