There are 2 Warlock spells where the old versions are actually better even when the old versions are at a lower level. The old version of Dark Siphoning VIII includes a heal component that the newer version doesn't. The old version of Rift V hits twice (only once on the new one). Even a lower spell tier of the old rift is more powerful as it hits twice.
I upgraded because the old version gets resisted a lot. But it would be nice if these were fixed. Also, why even keep increasing the level of Encase? It actually is like negative DPS because it does little and takes a long time to cast.