There are MANY of us who have returned to shots, and will never look back having doing so.
There is nothing magical about pumps... they have two sole benefits. The sine wave bolus feature and micro-dosing that's it. There is nothing more special about them. Pumps so called magic rests solely in the shortest acting insulins which they use period. If we exclusively use the same short acting insulin, and watch our numbers the identical amount of times you do with a pump, poof, we get the same results (ie the poor mans pump).
To answer your question directly, pumps cause all kinds of problems which are exclusive to pumps. Site infections, dosing delivery screw-ups, skin problems caused by reactions to adhesive tapes, severe costs, DKA when/if separated from said pump for short periods... crude artificial pancreas malfunctioning, or separated from them tends to generate serious problems. There are all kinds of issues, make no mistake.
If you want to walk away from it, or need to, put it in a lock box with your supplies and do not be afraid. You have learned an incredible amount using a pump for however long. Take the information and go forward... its not going anywhere, want to try it again, you can break it out of the lockbox and reattach it.
Mines been locked away since the last century, no plans to reattach until they are entirely closed loop and their marketing matches the results promised-advertised. When I used a pump I stopped using NPH. Returning to shots later on, I went with Lantus and all the issues/problems I had before the pump went away. Turns out it was the NPH, not me, my awareness, or anything else.
On one, i did solely what i was told and had nothing but severe problems long term.Off the pump, I am doing just fine thanks! Dont tell minimed...lol.