Doesn't change the fact that you can and many times benefit on skipping all teching so you can pump out the more cost efficient callin units instead.
Which again, will fix itself when you will make stock units appealing.
Demo charges need fixing but everyone knows you are a soviet fanboy so i don't count on ever making you understand.
Thats exactly what a fanboy would say
"I don't need to explain, everyone knows and U R FANBOI!"
Well, sorry to burst your bubble, but it doesn't work like that, if you believe there is a problem, you better explain it. Thou if you want to be a poo flinging monkey, your call.
Intended use of demo charges is a big BOOM under anything that walks/drives over it on controlling players demand. It does exactly that, therefore nothing is wrong with the ability.