The hybrid of a side scrolling strategy or platform strategy game is rare, but not unheard of. Worms is probably the most popular turn-based example. Awesomenauts is a popular 2D sidescroller MOBA. Here are some considerations in designing a hybrid of both sidescrolling/platforming and strategy.
Sidescrolling Consideration:
Y-Axis: Movement and positioning in the Y-Axis. Top down and other games have an equal positioning advantage as the X-Axis, but in sidescrollers, the Y-Axis is special.
A game that does not or does little to utilize the Y-Axis most of the time eventually becomes boring unless by design that is prevented with other considerations such as spacing and formation.
Terrain: Related to the Y-Axis, however, has to do with if terrain affects the sidescrolling gameplay. terrain can be platforms or flat or destructible (like Worms) or a combination. Terrain also may offer gameplay advantages, especially with gravity enabled.
Gravity: Also related to the Y-Axis. If gravity has an effect, then it will affect movement in the Y-Axis.
Spacing: Spacing refers to the fact whether or not objects can overlap with each other or displace each other or a combination (allies can overlap but enemies can't, for example)
Platforming Considerations:
There's not much difference in considerations with sidescrollers, however, platformers have a more focused with physics, so things like gravity is a given with a platformer.
Platforms: The consideration is not about the actual platforms themselves, but the mechanics of the platforms. Platforms here are more in line with dynamic terrain, such as moving platforms, spikes, and the like.
Physics: Just simple or more complicated ragdoll physics? More complicated physics may lead to unpredictability.
Jumping and other Movement Mechanics: Platformers have mechanics such as jumping, dashing, walljumps, crouching, climbing, and other acrobatics.
Strategy Considerations:
Formation: Will a formation of units be more effective or will a doomstack of units be more effective? For example, having archers in the back while having spearmen in the front and has to do with Spacing.
Positioning and Cover: Y-Axis and Terrain placements (ie having archers on higher ground) and also has to do with Gravity and Spacing.Will terrain prevent weapons from hitting?
Timing: Will timing be necessary for any of the strategy?
Pathfinding: Since strategy is about sending units with orders usually, how to handle pathfinding over weird platforms or terrain.
Construction: Will structures be constructed and how to aid a strategic effort? Will they be on terrain or platforms?
Time: Will it be real time or turn based?