After leaving a comment in another diary entry here, I was contacted by the developer of OSMiOS, a new, and after a quick examination of features, probably the most complete OSM editor for iPhone and iPad.
I was invited as beta tester and promptly installed the necessary gadgets and the app. A first glance on it shows me that it is as close to a JOSM replacement on any mobile device I have used. The features I have missed in Mapzen POI collector and PushPin is included, at least as far as the developer have been able to date, and it also allows for bulk upload of changes (rather than in place of uploading each change on the fly, this editor actually work offline, just like the more complete editors we all are familiar with)
Another feature that looks promessing is that it allows for downloading Bing aerials for offline editing. That will be of good help when preparing for edits on trips where I know mobile coverage will be limited (see previous post). The only obstacle it doesn't overcome yet is where it is lack of Bing coverage.
Also, the tag presets is probably the most complete with regards of predefined presets, and if the tag you are looking for is still missing, there is an "all tags" tab that allows you to manually edit, add, and remove any tag, even those unknown to presets.
After less than one day testing, I am very much satisfied with the program, I have sent one feedback with minor topics to the developer, and as it looks now, this will soon be the closest to JOSM you'll get on any mobile device