Fix-it sticks are great if you like a lot of little parts to lose, have too much money and are interested in cobbling together the tool every time you want to use it.

Folding multitools work great, not as well as a full-size tool obviously but much better than something that requires bits and shoving one end into the other to get leverage. I used a Crankbros M19 for 2 years as my only bike tool and it was fine. I'm not sure how something the size of a pack of cards can be considered bulky? Regardless, make sure you buy something of quality. Those $3 multi-tools often have undersized drivers and tend to have shorter lives. A good tool should only set you back $20 or so.

The chain tool on the M19 is only slightly harder than using a full size tool, I've gotten good feedback from smaller riders that it works ok for them. Due to the design it's also possible to brace the tool and use additional leverage to push the pin if needed.