Point #1) Spell components...I love 'em*, but they rarely see game play because of spell component pouches and arcane focuses.
My warlock recently lost his arcane focus, and in the campaign we're playing, I don't think he'll be finding another one or a spell component pouch.**
So, I looked into his nine spells and found that only four of them require material spell components:
1. A wing feather from any bird. Not a sure thing, but this is something that can often be found on the ground.
2. A pickled octopus tentacle. Yeah, I don't think I'll be finding that just lying around.
3. A cup of water. Hmm...maybe cups will become scarce.
4. A jeweled horn or a glass eye worth 100 gold. This brings me to point number 2.
Point #2) Costly spell components...I love 'em*, but players rarely ever know about them--and they tend to get upset when you point it out.
I plan on having fun with my warlock's new found interest in spell components. It's not a big deal. He has to choose nine spells known but with only two spell slots he rarely uses half of them. Those he does use often are verbal and somatic. But, I'll have giggle when he can't find a bird feather on the ground to save his life. It's a good thing one of his companions is some sort of wereraven who can fly.
* I know you don't, but that's not the point here.
** Again, not the point.