It was tough to place BO vs BG, ultimately i picked the BO because of its raw dmg output which can be similar to a pure dps's.
People passing out free immunities and not beeing 100% sync with theyr damage on unguarded targets was also a criteria that made me choose this.
Overall BO applies more pressure where BG has more utility. In a group i would always agree with your statement, there are different rules for solo however.
To the squig:
It is pressure that is easy to heal with a competent WP, i agree.
In solo queue however, there are different rules. You might end up fighting an enemy team that
a) does not have a WP
b) cant deal with it anyways because of the lack of gear
and even if they are able to, squig herder is still able to moral dump for TONS of raw burst damage which can be lined up with other damage abilities from 2nd dps.
Also its propably the most INSANE combination, if you happen to have a melee squig + dps dok in your party. Its an unbelieveable amount of pressure on everyone.
On top of that he has tons of mobility options which allows him to close gaps fast or get out of danger which makes him very annoying to deal with and gives him good survivability.