But, yeah colossuses for long range deep space exploration. Aside from being powerful, they're like mobile installations, and the colossus is already tons better than an arcadia based on how many ships it carries. With that many ships it houses on board they could send out fighters on several recon missions simultaneously. Not to mention it's a good bet that the colossus does carry other ships besides fighters.
The idea about huge ships on long range missions into unknown territory isn't so far fetched, i mean there's already a show about it called bsg

Aside from requiring jump nodes to go to other systems, the colossus could randomly warp to another part of a system it's already in which the bsg does all the time in the same star system or randomly warping to other systems. The only difference is that the colossus wouldn't be warping to other systems without the use of a jump node, after that idea, who says the colossus could be stopped at a blockade to a node? Unless you have a couple of ravana's or saths, that takes a lot of blasting still to destroy the colossus, the colossus could make it through some serious blockades and still be alive if not lightly, to heavily damaged.
Something that seems to me is that gtva really should do some exploration, they've been at their home systems for the past 30 years. Or are they too afraid they will find shivans in every unexplored node?
At least gtva has a way to close nodes after a skirmish with the shivans after exploring an uncharted node.
I wonder if the colossus has cargo bays?, or if cargo bays are part of the massive fighter bays on ships, probably that. In the future of gtva, meson powered bombs, even the big ones, i don't see why those couldn't be refined to be storable on ships for closing node missions.