I would agree that the prospector is too light for snowshoeing.
If you run hot I would look for one of the minimally insulated but reasonable wind protective materials like patagonia ready mix, patagonia figure 4, jackets made from pentex equilibrium stretch (you might be able to find the REI Pyrn for less than $50 on clearance racks), maybe powershield light, maybe scholler dryskin. If you tend to be a bit cold blooded then I would also consider Scholler Dryskin, standard Powershield.
The following is a dump of my experiences with softshells:
A summary of my experiences listing material and the shells I have had personal experience with. Temp range is my comfort range when engaged in aerobic activities going from lightest to heaviest:
Inertia (Cloudveil Prospector) So far seems like a good action shirt when I am moving fast (replacing wind shirt / base layer) in still or light wind conditions between 35-55F, and usable in warmer weather. Wind resistances seems about the same as my supplex shirt. The lack of insulation and wind permeability helps prevent overheating is moderate weather. If the wind is blowing hard wouldn't use it below around 40F because I would be too chilled. I have been pretty impressed with water resistance for such a light shell. Light drizzle rolls right off. Starts leaking in a heavy rain after 30-60 minutes. More water resistant and durable is better than my unlined wildshirt. [Appropriate for moderate spring, alpine summer and fall conditions]
Schoeller Dynamic (Cloudveil Veiled Peak & Arc'Teryx hybrid Alpha Comp) is decent in cool weather when facing abrasive conditions... but for general use, I find that the optimal comfort range is smaller than other soft shells. Dynamic started leaking in less than 20 minutes during a hard rain storm. I overheat in conditions that would be OK in an unlined wind shirt, and find myself feeling chilled at approx the same time as a wind shirt. The Alpha Comp is a beautiful jacket which is a bit more protective thans to the Gore-Tex XCR yoke and outer arms. [Spring skiing over light insulation or heavy base, and moderate weather climbing]
Unspecified Patagonia material (Ready Mix, Figure 4) I haven't used any of these jackets but they seem to provide approx the same insulation as Inertia (not much so they should be cool) while being slightly more wind, and significantly more water protective. Seems like a really nice material. [Year round use if used with insulation or heavy base in colder weather]
Pertex Equilibrium (REI Pyrn Jacket) More weather resistant than Inertia, a bit less stretchy than Inertia and is not quite as soft against the skin. In cool weather is likely to be a better choice than Inertia, but in warmer weather Inertia fairs better thanks to higher air permeability. [Appropriate for spring and fall conditions, high output aerobic activity in the winter]
Nextec EPIC (Patagonia Essenshell) is a good wind shell in cold to cool weather. Layered over a wicking base layer (with light insulation in colder situations) is where EPIC shines. EPIC doesn't absorb much what even if it gets soaked, so it dries more quickly than most soft shells. I found that it resists light sprinkle for several hours, leaks after around an hour in a real rain, and less than than in a storm. [Good as wind shirt over a light base layer when the temp is <45 F.]
PowerShield Lightweight (REI Mistral II) I have not used the light weight version of PowerShield, but it seems like a really nice material. It's a bit warmer and more protective than Equilibrium but lighter than most other soft shell materials. [Cool Spring or Fall, Maybe winter for high output aerobic activities?]
Schoeller Dryskin (Marmot ATV) is ideal when it was between 0-30F over a medium base layer so long as I wasn't facing really serious winds. This material is quite comfortable in warmer temp if you aren't active... I think it might have the widest comfort range of any shell I have used. I have been dry after being out for multiple hours in pretty hard rain. Wicks and breaths really well. If you want a Dryskin jacket I would first look at BeyondFleece's Cold Play Jacket. [Great for for spring and fall, high output winter activities].
PowerShield (Arc'Teryx MX) is very wind resistant and quite weatherproof, but not as breathable as some soft shells.I have found it appropriate for -10F to 20F type temps over a medium-heavy weight base layer. There are a number of PowerShield jackets and I haven't had a chance to look at them enough to suggest any one in particular. [Great for winter skiing, climbing, etc]
Nylon/Fleece Wind Shirt. Some people have found using jackets which are a nylon shell bonded to a light-weight fleece highly versatile because they can be worn as a base layer, an insulation layer, a wind shell, or for moderate rain protection. Examples of these include the Marmot DriClime Windshirt (the gold standard), Patagonia Stretch Zephur (I don't like much), Montbell Light Shell (lightest and least insulating of the bunch), Paramo Mountain Shirt, and Buffalo Teclite Activity Shirt. See Michael's Ultralight Clothing for a more detailed description of this strategy. Warmth varies depending on how thick the fleece is.