I wouldn't pull from Five Kage, most of the Rares are shifting out of the meta and the Sasuke[Sussano'o] and Ay[Fourth Raikage] are not worth going for in comparison to Naruto[Kurma Cloak] and Madara[Founder of Konoha]. The only thing is when Ay[Fourth Raikage] gets his skillbooks/skillbreaks he does become end game ninja as seen in China.

It really depends on far ahead you are planning. If you have a bunch of money to throw at the game why not use in some in Five Kage. But if you want to invest wisely for the next year plus don't worry about Five Kage. I'd also like to point out that The Monthly Arena Rewards will change over to Kage Summit Ninja Rares so you will be able to piece them together from that if you haven't already pulled some from free pulls alone by that time.

That's why I don't plan on pulling in Great Ninja War Treasure :)

It's all about how long the meta will stay with that treasure how soon you can get the ninjas from that treasure.

If you don't have enough scrolls to pull the ninja you are after when the New Treasure comes out and you wait for 3-6 months, you have lost 3-6 months of meta ninja time. You are best off saving your seals till you have a bank of them saved up and upon release of that treasure and a new shift in the meta use those saved Seal Scrolls so your new ninjas will be useful for longer.

For people who can't afford to change to every meta shift, you need to plan ahead like this or you are constantly trying to get ninja that have been out so long they are about to be replaced with something better.

I would also like to point out Five Kage Treasure has been out for over a year.