Rek'Sai top seems like a better idea than Jungle..

You're nearly impossible to gank with tunnels everywhere Your ult will work like Shen's where you tp to a lane(ult) to help someone else while having TP as a summoner You can easily help your jungler deny the enemy jungler with tunnels in and out of their jungle. Resourceless, nuff said on that Free hp regain from passive. Decent harass with reliable skill to trade Can splitpush mad fast with her AOE attack and tunnels to avoid being stopped along with that ult to get right back where she was

Considering you can be seen during her burrow I just can't see it helping at all for ganks. "Oh a huge fin is coming toward me, might wanna back up" Not to mention that ult..where would you put the tunnel in a lane? Nowhere you could just as easily bring teleport and actually tp into the lane rather than the tri bush or something

Also teamfights aren't even a question. All she has is a knockup that's so easy to avoid it's crazy. Plus you can be attacked while burrowed. I think Riot intended for this champ to be like nunu. A migraine for the enemy jungler but when it comes to the rest of the enemy team you're not that big of a threat