if bolts had even worse move speed, but no unpack time they whould be balanced i agree, because u can always kill it, they could not be op like slingers, who snipers use hit and run tactics to kill even champs, because they can't retreat if meatshield dies, like slingers, also they whould be a way to counter snipers.
i disagree with the last part, because more splash range whould make then too op, since u could just spam meatshield and they whould kill everything, rn they only kill 1 unit and damage 2-3 as u said to me, which is good, but not op o/ and if u increase theyr pop use from 2 to 3, or even 4, with needing p3 etc, they whould be only op in a really late game stage, which everything becomes op if u have enough time, like ecobot for 16 minutes or more scenarios