A 4 second delay weapon is to slow to be chaining your Combat arts.
If you parse yourself consistently over a week long period and average it out your auto attack damage is going to amount to the greatest % of your damage if your doing things right.
I'll try to break this down
without overcomplicating it too much.
I failed
Your DPS is going to consist of 3 things; variable DPS, fixed DPS and random DPS.
Your combat arts are your fixed dps. The reason I call it fixed is that your Combat arts have a fixed cast time, a fixed median for damage and if they are up, you can cast them. If you chain cast your combat arts or cycle them appropriately the damage done by them over a given period is going to remain constant. It's mathematically possible to determine the range of damage your CA's are going to contribute without knowing your haste/crit/DA percentages.
Your autto attack damage is your variable dps. It is variable because depending on how you utilize your combat arts this dps can change drastically across a fairly large range.
Your random dps is the damage generated by item procs/ripostes/damage shields/item effects/buff procs.
So you have a dps equation of A+B+C = Dps
Since your combat arts is your fixed dps the only way to really manipulate this part of your equation is to look at how one combat art might carry a buff or debuff that lets following arts do more damage. Take into account cast times and reuse timers to create the best casting order for your weapon choice and playstyle.
Once you have your fixed dps tweaked out you need to adjust your playstyle to maximize the % ratio of your variable dps(auto-attack) vs your fixed dps(combat arts).
If you chain your combat arts with a 4 second delay weapon you'll probably find your parse to be 40% autto attack damage, 50% combat art damage and 10% random dps but the overall DPS number will be much lower then it should be.
As you adjust your combat art timing and order to better suite your weapon you'll slowly see your combat art dps drop to 35% of your dps, random dps about 10% and your autto attack jump to 65%. You will also find your overall DPS number to be significantly higher.
In conjunction with maximizing this dps formula you can try and increase your random dps number by finding the best items with those effects on them that contribute to this dps. This is primarily the realm of mages but it can contribute to melee dps as well.
ACT is your friend, you should get accustomed to use it to examine your parse data in greater detail to make decisions on how you are playing the game.
Most of all, if your not having fun, then it's not worth it.