The main issue with the Scorpion for the traditional role that light tanks are used for is its lack of speed. 4/6 is not bad...but it's the "standard" speed for most Battle or Assault Lances (as evidenced by 'Mech designs like the Hunchback, Warhammer, Archer, Marauder, Orion, etc.). With that speed, it's not really going to be operating well in the recon role.
However, it would work well in lances as a "screener" for 'Mech Assault/Battle lances, as it can keep up with the heavy units while providing some long-range sniping cover fire and/or working as a "picket force" to help keep flanking attacks down to a minimum.
From an in-game perspective, though, their primary purpose appears to be to essentially work in a Light Battle Lance. The standard Scorpion Light Tank is a Brawler, so pair up 3 of them with a Scout tracked unit (like the GAL-100 Galleon or a Heavy Tracked APC), & you meet all of the requirements. You can also create a Fire Lance (generic) or Fire Support Lance (IFx ability) with the Scorpion LRM variant (kind of like how you can with the TR-A-6 Toro 'Mech). And if you pair up 2 standard Scorpions with an LRM variant & either the ML or SRM variant (both Juggernauts), you have a Command Lance. So you have the perfect combinations to make anything from a Company to an entire Regiment of Scorpions (1 of each Lance type for a Company; Battalion could have a Battle Company of 2 Battle Lances + 1 Command, Fire Company with 2 Fire/Fire Support Lances + 1 Command, or 1 Company with each Lance type; Regiment could have any combination of the company types). Note that, from a BV & PV perspective, the 25-ton Scorpion is nearly identical to the Intro-tech versions of the 20-ton Stinger and Wasp 'Mechs, so it's not outside the realm of possibilities to use them against Light 'Mech forces.