Spending game time to identify magic items works when they are rare. If you find one or more items every game session, you'd be spending all your time identifying and no time actually adventuring after a while. But they say magic items will no longer be mandatory in 5E, which could leave room for this kind of play.
Correct. This is exactly why I say the core needs to include all of the possible options right off the bat. The options should each be linked to the "Rarity Meter" you set for magic items in the game.
* Experimentation <=> Magic items are rare to very rare. They are so uncommon that there is no 'easy' way to test such items, unless it is a famous item in which case research of legends, stories, etc. is the best option.
* Ritual <=> Magic items are rare to highly uncommon. They are uncommon enough that only a long and involved ritual has been created to deal with identifying their properties.
* Spell <=> Magic items are highly uncommon to uncommon. Identifying them is primarily the role of those with a full understanding of arcane magic, utilizing their ability to manipulate magical energy to form a spell to identify an items properties.
* Skill <=> Magic items are uncommon but common enough that anyone with basic training in the understanding of the arcane (such as a Spellcraft / Arcana type skill) can use their knowledge to identify an items properties.
* Awareness <=> Magic items are so common (or magic works in such a way) that simply handling an item for a few minutes allows the properties of the item to be ascertained.
That covers 5 ways to identify and/or 5 levels of rarity for magic items. This should fit just about every game style out there and it would take up maybe 1/2 to 1 page of space. The "assumed" Core could be that items are incredibly rare (so a +X Flametongue would actually seem like finding Excalibur) and then you could immediately choose any number of other options you may want to allow for your game. For instance you could always allow Experimentation if that's what a PC wants to do, but the campaign could also support Spell & Skill options too. Or you could just replace Experimentation with Ritual or Awareness.
To me, this seems like a pretty simple and clean way to handle this topic and just about every flavor of how people may want to handle it.