Well if you wanna talk about gold flow, Runeglaive actually increases your gold flow over Magus due to it giving you mana back and helping you clear camps faster. You can farm harder in the jungle and your ganks should be more or less as effective as they were with Magus due to the spellblade proc, not to mention you should have more mana to use. You had to back a lot with Magus if you didn't have blue buff, purely because you would not be effective as a jungler without mana.
To the Sheen item complaint; yes it does hinder your ability to buy these items but I really don't think that Lichbane is a good buy as a jungler. It costs a hefty 3000 gold for an item that you have to build as a 3rd item minimum before due to the need for either a Tear or a Catalyst to help you with hefty mana problems in the jungle (or you hoard blue buffs the entire game). Building Tear or Catalyst sets you behind in your build path and doesn't offer a lot of combat stats to make you more potent in skirmishes or teamfights in addition to being items that you have to sit on for a long time before they are strong items (RoA and AA staff are both dependent on time).
With the old Magus you would get your jungler item, then get a Catalyst or Tear, then you had to get some combat stats;
or
were usually the go-to's as they gave a good amount of AP and some resistances to help you get kills without having to die for them. Next you would want damage amplification in
or
to make sure your damage is still relevant. So really unless you get fed, you won't be getting a Lichbane until way late in the game. With Runeglaive, you still get a bit of the Sheen item benefit, without having to further hinder your build to try and rush Lichbane after your jungler item and mana sustain item.
I actually liked IBG on AP Evelynn and sometimes on Diana if they had a fed AD champ or they were a high AD team, but it's only a minor loss. Triforce I don't think I would ever buy as an AP jungler (or really on any jungler unless I was snowballing really hard; it's too expensive) because many of the stats are wasted.
Now. I will agree that Runeglaive is a tad weak to those who cannot use the spellblade proc consistently, and I think it should receive an extra 20 AP to make it a really strong item all around. But I think it is miles better than Magus (except for Fiddles, rip), and it helps AP junglers considerably in the jungle, in combat, and helps them to maximize their build quicker than with the old Magus. That's how I see it. Peace.