Guild Wars 2

When casting an Illusionary Leap and your clone leaps through a combo field it correctly causes a leap finisher. When you then activate Swap, which too is a leap finisher, you will only activate a combo if you are currently standing in a field. It does nothing for any field between your original location and your clone location and neither for where you end up.
The same goes for Phase Retreat, it only counts as finisher on your point of origin. Fields at the end of your teleport are never triggered.

Now it is understandable that all combo fields between you and your target position are ignored, after all you are teleporting and not leaping. Though I think it should trigger leap effects on your target location too if no combo field was triggered on your original location.

With that in mind and the general wonky-ness of Illusionary Leap I propose the following change:

When cast, Illusionary Leap, similar to the 3rd chain in Torch 1-Skill, creates a clone besides the target, no combo finisher yet though the cripple effect happens on the clones first attack. This should greatly improve the reliability of the skill.
If you then activate Swap you are switched with your Clone an you cause a leap finisher on your original or clone location, wherever the first combo field is available. At the same time your Clones performs its leap to your target doing a finisher itself.

Bonus change: I think both Phase Retreat and Swap given the animation should actually count as blast finishers, though I don’t know if any other class has access to blast finishers on such short cooldowns and whether that would be balanced. Maybe have it as additional effect on the 20% cooldown traits for the respective weapon.

Thoughts?

Illusionary Leap is a great tool for Mesmers, provided it works – terrain can really gimp it quickly. I see your gripe, but there’s a few things about what you suggested that will probably not happen:
The Leap combo finisher happens where you stand as you Swap, because you can’t necessarily count on your clone standing in a combo field. The range is not too far on Illusionary Leap either so in the meantime you’ve cast the spell you can have moved to the same spot your cloned just jumped to.
You can however position yourself in a field before activating Swap – same goes for Phase Retreat, you can’t count on ending up on a combo field as you teleport backwards, but you can position yourself on top of one before firing it off.

And then there’s the clone’s buggy leap on actually casting Illusionary Leap. I want it to happen like you are saying, that it appears next to your target in a similar fashion to some of our Phantasms like the Berserker or Warden. Problem is, though, that we’d be able to easily get on top of walls and places we shouldn’t be. It still needs LoS like the Phantasms of course but if we could Swap places with anything our clone could attack, it’d cause some unfair advantages.

The point of the clone’s leap though is that it is an imitation of the Warrior’s sword leap attack, and so we can catch running enemies and immediately root them with Swap.

I know that a Hammer Guardian has access to a 5-second blast finisher, and while it’s not hard to stack Blast finishers on some classes that have multiple on longer cooldowns, I think it would be missing what was intended with this skill.