Its the patrol level scouts that make it a real issue as Ripple mentioned IMO, especially fantastic ones like the Corvan which has all-round firepower or the Vaarl which has Stealth 5 and SM at half speed.
I don't have a problem with things like the Delphi at all (Raid level scout? Knock yourself out mate - I'll take another Sulust

) although it really does depend on what PL you are playing at.
Saying that, usually the scout isn't that great a combat ship and is fairly frail as Greg mentioned (some of them don't even have Stealth!) so you should get something of value for giving up a "combat" choice. Again this could be one argument for imposing some sort of ship rarity trait I mean the fluff on the Vaarl/Vaarka says something about the Vree rarely committing more than 1 of these models to any engagement...I hardly field any other Vree ships!
(Aside:
My typical 5pt Vree fleet would be something like:
Xaak (Battle) - 2 points
Xixx (Skirmish), Vaarl (Patrol), Vaarl (Patrol) - 1 Point
Xixx (Skirmish), Vaarl (Patrol), Vaarl (Patrol) - 1 Point
Xixx (Skirmish), Xixx (Skirmish) - 1 Point
Although I may replace a couple of Vaarls with Tymm fighters depending on opponent and if the scenario allows JPBs (only joking on JPBs

)...