I have to agree with Irish here, scatter serpents are vastly superior to ELM. Just wait until you face a chaos dude that has two hellturkies, the Fateweaver, and a flying DP or two backed by screamers and horrors with a cultist lord blob. If you where playing me, those rangers would be First blood fodder with my serpents, that or the lord.
I am not dissing your list at all, I think that many WG is golden, I just think you can bring up the kill ratio much higher. Play a solid tzeech list, prob the most potent list available. You will need the higher number of twin linked shots to force a bunch of saves.
If its just friendly games, ya sure ELM are fine but there is a very solid reason they wont ever been seen in any tournie finals tables.
Ok, took another look at your list. My issues, beyond the ELM, are those of synergy. You have a grand majority of your army moving all over the place leaving some static or slow moving units without support. The rangers, platforms and lord would get changed for me. Those three platforms are going to get eaten by a single drop pod sternguard unit or some termies, rangers are nothing against fearless units (alot) and the knight will get caught mid table turn2/3 and dropped.
I would like to see the knight turned into a lord and given the Suncannon package, that way he can sit with the platforms and lob blast templates with them, OR you could pull them and the lord and take just the knight that can keep up. Dump the gangers and ELM and pick up some 3 man windriders and you have a deadly list.