1) they are way too costly and usually not covered by insurance
They are expensive, but if you look at ANY device for medical/disability purposes, they are all ridiculously expensive and often not covered by insurance and/or provincial health coverage. So this is not really a "pump" problem but a more general problem of companies charging ridiculous prices for technology that people need. I have a braille-tablet-computer type device on loan for school which costs $7,000 for, essentially, an iPad (and yes, it's just as feature limited!). Which is ridiculous but, well, I need to be able to read, and all such devices with refreshable braille displays are just as expensive.
2) you still have to prick your finger to test your BG because they are often not accurate (i still can't believe this?!)
This is not a problem with pumps. This is a problem with CGM devices which are completely different. Pumps are starting to have CGMs integrated into them, but pumps came out LONG before CGMs did, and there are many people who use a pump without using a CGM.
it's not really like a pancreas, you must still figure out your dosages
Pump aren't like an "artificial pancreas" but, then, they have never purported to be automatic like that ... Overall, pumps offer way more flexibility than you can get with injections, although not everyone needs that flexibility. It's not possible to do temporary basal rates, extended boluses, "super" boluses, or stop delivery completely with injections.
4) they need to be replaced more often than i think is acceptable
Pump companies and insurance companies "recommend" that pumps be replaced every four years, but this doesn't mean they have to be (with the exception of the Spirit which is set to stop working at four years). I have a Cozmo from five years ago that is still working fine and that I would still be using if not for the fact that it's not covered under warranty anymore and I can't see the screen at all (compared to the Ping). So the problem is not with the pumps and/or their design, it's with the companies wanting to make extra money by having people upgrade to the newest model.
5) they are bulky and won't fit well under nice clothes
I actually think the main problem here is not that the PUMP is bulky but that the INSULIN and the BATTERY are bulky. Pumps these days are not much bigger than meters. Both pumps I've had have had a majority of their space dedicated to a cartridge and a battery. If they could find a way to make insulin "smaller" and use a small watch battery, then that would go a LONG way towards being able to design smaller pumps.