Will this playstyle work? Yes. Will it be compeitive? Yes. Is it my style? No.
The only real problem I see with this list is it's lack of ranged AT firepower. You've got 7 DLs, granted, but if your plan is to turbo everything as fast as you can towards the enemy, you're not going to be able to fire them. The blasters are nice, but at 1500, I'd recommend a sniper squad or 2 instead of one of those raiders.
Also, I believe that raider squads should be flexible, and I wholeheartedly support this belief by giving them some mobile firepower (SC + Blaster, as Khodexus says) and a sybarite with an agoniser. Enough punch in CC to deal with some of the lighter targets that you don't want to throw your wyches/incubi at, but enough firepower to down light infantry troops that threaten your scoring units. A very flexible unit in the army.
Now to answer some of your questions
a) Will the tactic actually work with the units and raiders frailties. I'm used to Eldar tanks and their indestructable like ways, i am expecting to lose 2-3 vehicles in my march across the board but from experience of others am i likely to be taking much worse losses? If on average i am then i need to reconsider the whole army because it can't afford too many units on foot mid table.
Yes, if you keep your raiders behind cover or behind another raider. It's going to be hard to hide a raider with 5th ed RLOS rules, but the least you could do is get a cover save.
Also, don't be too scared about units mid table. In standard fifth edition games, the farthest you can be from your opponent after a 24" turbo is roughly 12". Easily enough for a charge range. However, what you should be worried about is your units shot out of a downed raider. Keep them in cover (or make some with a flying raider) at all times.
Note: I'd recommend putting your troop raiders in front of your wych raiders.
b) Is there any alternative unit/weapon i have not pondered over already that would slide in well. I'm fairly confident there aren't any units due to the limited selection choice and the fact that none of them would really fit in except maybe Ravagers
Well, if you're going for quick assault theme, Reaver Jetbikes could be what your looking for. Along with the great new rules for an RJB lord, you may want to look into them (PM me if you have questions).
Ravagers aren't as effective in a close combat army. You're always worried bout shooting your own guys with dessies, and the tri-lance build is less effective.
I'm not resistant to your idea, in my original list all squads had Spinter cannons till i played some 500 pt games vs tau and marines and felt they were hugely over rated for their points cost. Unless you are using proper gunboats then i just don't see the practicality of them (stats wise). In a way i'm more playing devils advocate, i don't just want to jump on board any suggestions where the poster may not be fully aware of the tactics or planned game style. That would be brash indeed. I don't have my mind made up in the slightest, every time i take a glance over the list, or dare pick up the codex i find myself torn between making changes. If anything i have taken on board the scissorhands/horrorfex and night shield suggestions. I will probably playtest with each and see which works out more useful, so thanks for that.
Against Tau, I can see where splinter cannons would fail you. Against orks (the most compeititvely viable tournament option) or guard (who, after getting their new shiny codex, GRRRR, will come in greater numbers), SCs are very useful. Your mathhammer described it all. 1.77 kills with T3 and a 5+ save? If you have 6 pt guardsmen, the SC has made it's points back with a little to spare and only being fired once. If, however, you were shooting at, say, genestealers (with or without EC), you could wrack up two or three times the points of it in 1 round of fire.
Edit: After reading your first post over, you said an SC could kill 0.44 of an MEQ each turn? If that was a sternguard or vanguard vets, you could make your points back in 1 turn. Even if it was normal marines, it'd still be worth it, even if you only shot it once.
Hope that helps.