I've never liked the SHIVs personally, as they cost more to research/build/setup than a human soldier, along with the other downsides you've mentioned. I'd much rather bring a rookie/squaddie (or otherwise underleveled soldier) along for the ride than a SHIV if I have the choice. The investment I'd make in a SHIV I would rather make in gear or other base improvements. A properly equipped soldier will beat a SHIV hands down in terms of versatility and firepower. Even if the squaddie dies, I get to keep his gear, although the destruction of a SHIV is a loss of all the cash/resources invested.
However, I think the root problem here is that you're losing scouts frequently. Stop doing that, and you'll be much better off. I explained my strategy in this answer, but the general gist in this situation follows.
If you don't know where aliens are, cycle through your squad until you've got your scout selected. Use the scout to look for aliens in the first half-move of your scout's turn. If you find them, have the scout retreat and set up an overwatch ambush with the rest of your team. If you don't find them, move everyone up using half-moves, and set up a perimeter with overwatch and wait out the enemy turn. Your scouts should generally never engage directly.
(There are exceptions and caveats - for instance, on a terror mission where you need to move quickly, you might opt to be a bit more aggressive. If you've got all the time in the world, though, use it.)
When you find aliens, you're generally outnumbered - your one soldier discovers a group of usually at least 3. The aliens then get a "free move" to set up defensively to react to your position. This puts you at a disadvantage, and you can't afford disadvantages.