Shadowverse

This legendary isn't available, but there are plenty of other Heaven's legends, including new ones.

I have the opposite situation with Heaven – I have Aegis, but almost no other legends. That's why I always played Storm.
Actually, it's funny, I was recently complaining about the lack of dust, and then I went to my collection (I haven't played for a long time, I forgot what legends I had there) and was surprised to see full sets of Elf Queen, Anomalies, Fairy Princesses (normal legends would have dropped on Forest), Hulking Giants, two Beast Dominiks... I started slowly disenchanting this stuff – and that's when the dust appeared.

Since in the next expansion, Sahaz-Ryu, Bahamut, Ferwor, and Salamandra will already be rotated out.

For some reason, it seems to me that if Rune and Shadow are nerfed, then in the new expansion, we might see a "return of the living nerfed-2" – instead of the current Ectar and Catacombs, we'll have PDC paired with Sybil (although the latter never really left). However, without Ferwor and Salamandra, it might not be as good.
I agree about the Portal matchups – Rune also seemed like the most unpleasant one, but at my rank, they have all disappeared now, and the ladder consists of about half Shadow and – unexpectedly – Portal. And if before, Shadow spammed followers along the mana curve, polishing all this with the Prince and one of the "doctor 7" on the seventh turn, now there are some strange, slow builds, which have become easier to beat.