It's true that selling on eBay has become more difficult, even somewhat risky if you're not fully aware of the potential pitfalls. I'm not afraid to sell, but I am more careful than I used to be.
Tracking will help you if you are dealing with an INR (item not received) claim, but it won't do anything for you in the case of INAD (item not as described). And INAD claims can cover a lot of territory. On the other hand, U.S. buyers generally expect tracking, so providing a tracking number can often serve to reassure a buyer.
The real problem with selling on eBay and dealing with shipping, from my perspective, is that it isn't just up to the seller to deal with any shipping issues and make a customer happy, end of story. Nowadays on eBay if you don't have tracking and the buyer opens an INR claim, then you'll get a defect. Too many of those and you'll be out of business here anyway.
In the end, you have to assess your risk tolerance against your profit expectations. If you can use tracking and still make the profit you need to make to continue your business, then it is a reasonable option. If the cost of tracking will wipe out your profit, you have to be prepared to either take occasional losses through INRs/INADs or else keep your volume high enough to cover those eventualities.
There is no easy answer, but personally I tend to tailor the shipping service to the item value and type. I won't send a $200 dress to the U.S. without tracking, but I will ship a $15 pattern by Light Packet (no tracking, no insurance).
Lastly, in my view, communicating with buyers at the time of the sale can make all the difference. Send a personal message to the buyer (through eBay Messages) at the time of shipping, thanking them for the purchase and providing them with an ETA. I always mention Canada Post in there somewhere too, because Americans do tend to forget that we're actually another country.
