But your combination is fine too... Isn't so different... You can port around your warriors and that is useful too.. So you'll be fine...
I must admit that in my playtesting I had lot of problem with hordes and 2+ units that get to you fast, like termies.... mine first upgrade of the list was idea of 5 more destroyers (at 1750), but I'd increase dakka power while not working on my problem (and that problem makes me non-competitive)... So I decided to add c'tan... And as much as everybody prefers deceiver, i went with nightbringer and must say I love it... It makes it impossible to get within 6'' of my nightbringer with boyz and similar s3 morons (like nidz), and makes me pretty damn dangerous in
cc... With liths you can block
los to him so that he can't even be scratched with long range fire... Just love it...
I'm planning on further expansion of my 1750 army with upgrading my lord (for now he is warschyte and rez orb at 1750) with fear aura and giving him 4-man pharias squad to make my army even more dangerous (with ld7 in 12'' and 24'' fear)... Rest of pts for destroyers... And usual castle in tactics
Just a few notes to ponder about
As for your army, if you didn't test it yet, you'll see that a lith / destroyer army is quite mobile... You'll be able to keep up with fastest armies and stay away from slow ones... but still hordes will be almost impossible...