i read the post about skills dps but there are more things that matters:
-when you use combo , skills are faster with x% (how much is that)
-for example when u have a skill with cast time 4s and a skill with cast time 2s and if u calculate that the one with 2s does more dps you can be wrong because you must add the time between the skills cast and then calculate dps

eg: x1 skill does 1000dmg/4s
x2 skill does 500dmg/2s and 500 500/2s (interval between casts) 2s

in this case x1 skill is better ...