Suggestions could include:
No limit on number of turn-ins for the final day before his tour restarts.
Double number of gift of the traveler.
Increased number of items in each gift (25 candies, 10 summoning stones etc).
25 of X trophy, then he asks you for 25 of Y, then Z.... until the day is over.
Free royal gift for every gift of the traveler received.
Chance of receiving 5 platinum with every gift of the traveler.
Perhaps even an escort quest, to escort Nicholas to a zone in the general direction of his next zone.
If the Devs were really generous, perhaps his last location will be in Tyria and we could have a massive multi-zone escort quest to his first location of Regent Valley. I'm sure it would be a great finale, if players received 5 gifts for each zone escorted through.
Or better still, imagine this quest text after handing in his last request:
"For a minute there I thought I wouldn't make it. I had to run so fast I left behind a lot of my things. That infernal demon finally caught up with me on my way here.
I had my suspicions I was being tailed, which is why I tried to throw it off my scent by going from continent to continent. What? You thought I wanted to take the long scenic route?!
If this demon isn't stopped, I may not be able to collect my things and continue my journey. Kill it for me, and bring back my things, and I may find my way to rewarding you with some extra gifts."
The task would be to kill a really large Vengeful Aatxe or something equally sinister and take Nicholas' bag of items back to him for the quest reward, worthy of a grand finale.
Sometimes i wish i was a Dev...

Any other suggestions to add to this? Hopefully the live team are capable and willing enough, plus not too busy to do SOMETHING.