OK thanks, seems like it is not as good as I thought. Any other Feat suggestion? Thoughts on my Elemental feat?
Oh no, MI is great! You just have to REALLY consider wich list you're going to get those extra cantrips/lv1 spell from. And while you're doing that you should consider A) wich invocations you'll want, B) wich bonus spells from your patron are available. You might also want to consider wich spells are "in-character" for your warlock, not just wich ones provide the most bang.
For ex;
When my 1/2ling warlock (fey patron, chain pack) took MI at 4th lv I chose: Light, Mage Hand, & Expeditious Retreat (from the Sorc. list).
Light - because I'm a 1/2ling & I don't see in the dark. That's kinda important.... I also don't want to always be carrying a torch/lantern. (Neither does anyone else, really.) And as cool as the devil sight invocation is? There were just other invocations that fit my character much better. Like the one where I can cast detect magic at will! (trust me, it completely fits the character to do that).
Light is not on the Warlock spell list.

So I had to go shopping elsewhere for it.
Mage Hand - another extremely useful utility. Especially if you're a 3' tall Halfling.... Do you know how many things are naturally out of my reach??? Well not any more.

And it's provided a lot of amusement as well as utility.
Expeditious Retreat - I can, will, & do, run the heck away from danger! I had this spell from the warlock list initially for a few lvs. But how it played out at the table revealed that I really only ended up casting it about once per day. So it was really costly to keep it prepped as one of my 2 spells.
Taking it via MI allowed me to swap it out for something else, freed up that slot, and still allows me to flee at high speeds if the poop starts hitting the fan.