Hiya.
As a DM, I've always held to the standard of "No same-core class combos". I've been doing this since 1e when I made a Ranger/Paladin that was, simply put, crazy-nutzo-powervulz. Since that day, I do not allow 'same core' multiclassing. In other words, you can't have a Sorcerer/Wizard, or a Cleric/Druid, or a Fighter/Barbarian, etc. This restriction made even more sense with the advent of 3.x/PF...and I'm happily carrying it over into 5e (assuming I even allow multiclassing...still not sure on that).
That said, I really don't see the combo(s) listed above as game-breaking. This does give me hope for allowing multiclassing at my table. Playing a character ever weekend for a year or two just so you can say "See! I have an extra 45hp and can do lot's of damage...well, at least two or three times a day, anyway! I rock!" seems kind of...well, I won't say it. It's just not that "wow" as far as I can tell. I can say that it's a great way to waste two years of playing a fantasy RPG as far as interesting, character-driven role-playing potential is concerned. I'm sure someone can make a good and interesting "Sorlock", but, really, if they are doing that for mechanical reasons first, then tacking on a "RP reason" to justify it...er...o-o-k-a-a-y. Whatever floats yer boat I guess!
^_^
Paul L. Ming