I wrote a big long piece on this topic yesterday. And then forum lag lost it!
Anyway, I would interpret "being able to see and talk to" your patron as "they will appear in your camp".
Now my feeling is that the might - might - work similarly to paladins. After all, that mechanic, and the oathbreaker-dude who appears in your camp, are already in the game. It's a lot easier to copy-paste an existing mechanic than do it differently each time.
Which would mean that:
* if you annoy your patron they can temporally remove most of your powers (or otherwise punish you), until you do something to appease them;
* It may be possible to change patrons without doing a full respec;
* none of the patrons will be at all benevolent. Because that would make that subclass much easier. HORRIBLE BOSS is a feature of the whole class.
If we assume that Wyll's patron is the prototype for all patrons, we can assume that the others will each get slightly less content. So it will probably be only one option per subclass. Having a big long list like clerics' would mean much less content for each option, and probably no personal appearances.
Now I am going to wildly guess that the patrons are already in the game. Raphael is the fiend, Auntie Ethel is the fey, and Daisy/Champion is the GOO.
