c'mon, hovering over and reading all ships and their numbers takes several seconds. looking at blips and seeing 'their fleet is quite a bit larger than mine' takes one second.
Re-doing blip sizes or whatnot will make reading plain numbers much faster than looking at the blips.
Seeing "Javelis x100" is much better and faster than "medium blips" 
Sorry, but I see absolutely no logic in your suggestion. If you need a quick side estimate, you look at the blips. If you need a quick strength estimate, you hover over the blips. Comparing numbers is much more intuitive than comparing blip sizes. What the hell is "I have 3 large blips to his 5 large, but I have 10 medium blips and he only has 5" supposed to tell you?
It's a poor comparison in and of itself, because a heavy cruiser isn't always scarier than a bomber squad. That's why you look at the exact numbers. I can have no heavies and the enemy can have 30, but I can still take them out with all my bombers.
Or how would you even distinguish between fighters and bombers? Or light frigates and long range frigates? They're the same size, so it'd have to be the same size blip.. but 50x fighter is quite different from 50x bomber, and 100x cobalt is different from 100x javelis..