Either buff Ivern's movement speed or his CDR

Before 7.22 rune/mastery changes, the most common rune page for Ivern included 3 MS quints, which is about 4.5% bonus movement speed. For Ivern's original masteries, players would take Intelligence which provided 5% base CDR and brought the cdr limit to 5%.

Ivern's base movement speed is 325 (making him the slowest jungler in League of Legends, besides Kindred, who is ranged and has dashes), and 4.5% bonus MS from the old runes would bring that amount to approximately 340 MS, and further increase MS masteries giving him 350 out of combat MS, and with the later additional purchase of boots and support items like ardent censer and knights vow.

This movement speed was crucial to Ivern's ability to clear camps (by applying his passive), roam and gank/support his team, as well as escape invades, especially against the current "meta" junglers like Shyvana and other "duelist" junglers that currently benefit greatly from Press the Attack and/or the Domination runes and have a faster early clear than Ivern.

As of now, the most common Ivern rune pages consist of the Guardian Rune as what I think sound replacement for Windspeakers Blessing, followed by a secondary choice between Inspiration and Sorcery.

For the Inspiration Secondary, Cosmic Insight is considered a must have, since it not only replaces Intelligence mastery but also provides important CDR for item actives that are core on Ivern like Redemption and Locket of the Iron Solari, and summoner spells Flash + Smite.

For the Sorcery Secondary, a combination of Celerity and Waterwalking (to replace the 3 MS Quints and the Explorer mastery, respectively, and not replacing the out of combat MS offered by Wanderer mastery).

While the old runes and masteries would have allowed Ivern to have both the bonus movement speed AND the 5% base CDR with 45% CDR limit, the current reforged system forces players to decide on one or the other. Going Inspiration forces Ivern players to deal with 325 MS in the early game, which severely hurts Ivern's clear speed, his ganking speed, and makes him vulnerable to early invades. Going Sorcery forces Ivern to sustain a CDR nerf from the Runes Reforged patch, and also miss out on various tools the Inspiration tree offers like Future's Market, Biscuit Delivery, Stopwatch, and Hexflash.

So, either Ivern needs a movement speed buff or an ability cooldown buff.

For an ideal movement speed buff, perhaps changing his base MS to 340. I came up with this by averaging the base movement speeds of the two champions I think are most similar to Ivern: Leona (335 MS) and Nunu (345 MS). This was also Ivern's base movement speed with 3 MS quints in the old runepage, and not counting old masteries.

For an ability CD buff, lower Triggerseed/Rootcaller by one second (smallest whole number from 5% of the current CD) and Daisy by 10 seconds.