I really doubt its the saw that has the problem; if it is, its not an epidemic. I have had a few Olympics and still do have three, have a Deere 36, 2-52's and a 56 and have seen my share of the rest of the Efco's in the shop. My 480a is nicknamed the Exxon Valdez, as it will leave a slick on the ground if you are not cutting wood and rev the saw for any length of time. All my oilers put out more than enough to lube the recommended bar sizes, and the only problem I've seen in the shop is improper fit up of the bar. A couple of people have left the spacers in them when they assemble them, and one guy discarded the metal plate on a 152. The one oiler I've replaced was on a 3600?, a smaller saw, covered under warranty although I suspect it had more to do with the vent being clogged; again, a maintenance issue, not a design defect. These saws have some defects and design issues, as all seem to, but for the average Joe Homeowner they stand up well, and the few commercially used products we see they don't have any more problems than any other brand, and fewer than some, including the big two.
Oregon started the angled hole in their bars to "improve oil flow and reduce clogging". It seems to work for me. I will say I keep my chains fairly tight, and have the fortune not to be running chains on these saws right to the nub of the cutters. If your sprockets and drivers are wore, if the bar groove is worn, if you insist on being a west coast logger with a 1/2" of slack in a 18" bar, or try to run bitumen or 140W gear lube for bar oil I doubt drilling the oiling hole will keep your bar from being clogged up, but its your saw and results may vary. Some people insist that they never have to clean a bar groove, mine usually have some stuff in them and I have a groove cleaner on the depth gauge so I use it when its off the saw. I have seen Husky badged, Stihl badged, Deere badged, Efco badged, Silver Streak badged bars all have the angled hole, I assume Oregon is making them and selling them the paint to put on the bar.
That said, I have also seen the newly painted/stlyed Oregons without the jet style hole, so maybe they are rethinking the concept.