Here are a bunch of logs for my ele, I don't raid a lot anymore so probably ignore the mythic ones but yeah just take a look at anything you want:
https://www.warcraftlogs.com/rankings/character/9385320/latest/
Yeah get rid of echo for EM as soon as you get legendary ring IMO, because the ridiculous thing about ele damage is the only time the spec ever does decent output is your ascendance burst every 2 mins aside from times where you can spam chain lighning on 2 or more targets (I believe CL to be of use on tyrant etc.)
And during ascendance, echo does nothing for you so you want to go into it with a ton of haste - you want EM and 4piece proc for as much of ascendance as you can, maybe if you can use a GCD during asc to hit a 15-20 fulm ES to maintain it again that might be good but I'll leave that one to the theorycrafters as it would be a waste if neither 2pc or 4pc proc for the use of that 1-2 GCD.
Also, it looks like nobody has mentioned this, but you have class trinket so SPEC ELEMENTAL FUSION - then you get 2EF charges and Unleash Flame for a triple buffed flame shock plus the trinket means it ticks something ridiculous - on my best mythic council log, flame shock accounted for 27% of my total damage output for the fight, as I was maintaining fully buffed flame shocks on all 3. Compared to lava burst on that log was 23.6% so it can be very powerful.
On my best Heroic Archi log flame shock was 19% of total and lava burst 20.86% so I'm saying always use this even on single target fights. The only time it's not important to buff flame shock is when a target is going to be dead within 30-60 seconds anyway.
There is an argument about unleashed fury vs. primal elementalist, I have tried both and my sims put unleashed fury ahead by a bit, plus it means more dmg into ascendance/ring at the cost of a GCD (which you would probably be using anyway to buff a fire cast) so I think UF is the good choice.
And just a matter of opinion and more general raid utility than dps, but I prefer astral shift talent to soak things in heroic like shadowfel burst on archi, black holes on xhul or just any situation, rather than natures guardian which is passive and useless if your tanks don't suck. Maybe suggest looking at your logs to see how often Natures Guardian actually procs for you (and whose fault it is hehe) to decide whether you want to keep it.