Hmmmm.....
I wouldn't worry so much about "complete"....I mean....What does that mean exactly? I feel like I have a complete Skylanders Spyro Adventure collection....but I certainly don't have Flocked Stump Smash or Stone Whirlwind and a whole mess of other variants....
My Giants collection was complete...even though I never had Terrafin Series 2... (I can hear Wiisdom recoiling in horror at not having a Terrafin, not to mention arguably the best Skylander pose ever...
)
As a matter of fact, I only got that Terrafin about 2 months ago!
So what I mean is...your collection is complete when you have hit the goals you deem are important and financially reasonable to you. (All core Skylanders...Excellent!, Cores with 1 Trap master per Element...Awesome!, etc, etc)
That said...I think Enigma is pretty cool with a unique move or two, if you have any Skylander of an earlier series than the pressure is really off in my opinion to get a newer one. Fist Bump is all new so I think a good choice.
as for Trap Team remember...They don't dissapear as the new game comes out..in fact, having some left over to get at your leisure has some advantages. They have more deals on the older stuff...(deals often come as a buy1-Get1 some % off- I have often not had a 2nd "other figure" I needed to take advantage of the savings. )
Me personally...for Trap Team...I wanted 1 of each core, 1 Trap master of each Element and 8 traps. In addition, I wanted to make no purchase without SOME kind of deal...B1G1 40% off, buy a trap, get a second for $1., etc, etc. I did pretty good with that!! I exceeded my initial plans but i will certainly not have every trap.