Remember that battery powered tools are generally considered to be ligheweight purpose tools compared to the line powered tools. For specific irritants, here are my opinions:
1: The chuck cannot be used for small drills The collet (not a chuck!) you have is probably the 1/8" one and there are three others in the set which go down to something that can hold a @120 bit (I have one and have used it in my own Dremel) so anything from 1/8" to something that you won't want to handle is holdable in the Dremel with the right parts. There is also a real chuck that can be purchased if you want to use that.
2: The button which locks the chuck in place is located just where one would put one's fingers when using the tool. It does make an awful noise when one does so. You need to rotate the tool a bit so that your finger lays somewhere else.
3: The re-chargable battery is a 'touch fit,' and after some months of intermittent use, no longer touches the contacts on the body of the tool, so that I have to press it while using it. Contacts sometimes get bent the wrong way. It sounds like you need to reach in and bend them so that they make good contact.
4: The 15,000 rpm switch gave up after just a few times. No answer here. I don't own one of the battery powered ones so I really don't even know what that switch is.
5: Ther re-chargable battery has no indication of which is the proper way to insert it into the body of the tool. One of the things you just have to learn, apparently. Most battery pack systems tend to have a preventer from inserting the pack the wrong way. Apparently Dremel didn't do that on that tool which would be a true case of bad engineering.
6: thge case in which it comes is inadequate. What somebody considers inadequate is another's delight. Blowmolded cases tend to be usable only for the original stuff that came with the tool and don't accept any more accessories. They also tend to require the uninstalling of any bits in the tool in order to allow the tool to snuggle in there right. That is sort of the way that the makers all make them. You don't see cases for drills, for example, accepting a drill bit in the chuck when putting back in the case, do you?
-- There are more Democrats on the Calif. Special Election than Republicans! Go count if you don't believe me! Bob May