I'll echo all the good things said about this episode (excellent points by the way The Big Al). I'll also add that the animation for the time portal was quite a bit fancier than normal, though such neat effects will start becoming more common now I think. Also, it was a nice little detail that was added by Callista that the exact same person can't exist in the same time as their past or future selves for too long. One wonders what would have happened if she stayed too long. Was this little remark only in the dub?
Other good points:
Meowth calling out to blame the "twerps" for getting them lost.
We've often seen a Psychic Pokemon lift objects before, but not often have we seen them lift and then blow apart the objects into dusts and bits of stone. I guess that is why Callista couldn't use Xatu to do the job (because really, Xatu should have known an attack that could do the same thing), there wasn't enough room to put the rocks somewhere else, but blowing them apart would have put them at risk and I guess Xatu couldn't use a psychic attack and Reflect at the same time.
It was a rather sedate episode, but I wouldn't really call it boring, just different. I certainly see why some wouldn't see it as their cup of tea though. ^_^
It would seem that the future self wanted to share all her discoveries with her younger self so she wouldn't waste her whole life discovering the same things, but did she?
I got the impression she simply wanted her past self to use her time more wisely. She noted that she regretted the number of years she struggled to convince her parents (and others? ) to accept her profession, all for nothing, and wanted her younger self to waste so much time worrying. She was convinced she could change her future for the better if she did that.