Roar/Whirlwind are interesting moves, but without very-good defenses, the negative priority limits their usefulness for scouting. So, something that could be interesting and really help it with scouting would be to give it a move to the same effect of Roar/Whirlwind, but with normal or possibly even +1 priority.
Of course, there would be obvious problems with such a move if left unchecked. Set up Stealth Rocks, switch to Scarfed CAP7, and use the move until your opponent dies of SR damage. The solution to this would be in the mechanics of Protect. That is, have the move run off the same success-meter as Protect and Detect. It would be able to force out a threat and cause maybe one more switch if it's lucky, scouting the team as it does so. It would be a very good potential move, but not broken, with Protect+the move and Scarfed uses of the move stopped from being broken by the mechanics, with Protect and Super-Roar being tied to the same success-meter, a 50% success rate on the second turn.
Another interesting thing that's getting brought up is the abilities. Both Frisk and Anticipation are very good abilities for a scout. Anticipation is a bit lacking though, but if we end up going for it and want to replace it with something a bit better, we don't want to make it too strong either. The best way of handling it, that I can think of right now, would be to mix it and Forewarn, displaying the types of any super-effective moves the opponent has on you. So, if this Pokemon has say electric and ghost weaknesses, and it faces Rotom, the ability would say something like "Rotom has Ghost and Electric moves!" Helpful for scouting a Pokemon's possible moveset, with still a bit of mystery to it since the actual moves aren't revealed. In other words, it would give more of a view into the Pokemon's filler/flexible move slots, which can be very helpful for determining which Pokemon you should be able to switch into it.
Frisk probably will still end up being the better route to go though, since it will allow you to get a feel for the actual type of moveset the Pokemon has, allowing for safer switches.
As for typing and stats, it should probably have numerous resistances and at least somewhat respectable defenses so it's able to switch in and do its job. A SR resistance would probably also be a good idea for the same reason. A pretty good speed that would probably be needed to best allow it to scout, being able to get some information before the opponent can KO it. But it can wind up with great defenses and a good movepool, it could also be able to do the job with a slow speed, but I don't think that another really bulky Pokemon is what the metagame needs, so that probably won't happen.
Finally, there's the Pokemon that we want it to counter. These will probably be things like Salamance, Lucario, and Infernape. Thus, it should have pretty good offensive stats and moves in order to threaten and deal with them.