Yes, 13.1 is to be maintained for about 18 months in total (actually a bit more since 13.2 has been post-poned).
Like any other version before (which haven’t gotten libreoffice updates either). The 18 months support cycle at least hasn’t changed since 11.x.
Then it will get continued support by the Evergreen team.
I have no idea what their plans are, but I would think they won’t be very keen either to do feature updates, as they only have quite limited manpower. Also Evergreen support is also only supposed to provide bug fixes and security updates.
Anyway, discussing this here with me won’t change anything.
You do have the option to install from OBS or from the LibreOffice homepage.
LO 4.2 (or 4.3 even, I don’t know the LO release plans) will be part of the next openSUSE version, but most likely never be released as official update for 13.1. And that is not my decision.
You will get bug fix updates when/if they appear though.
If you find a bug in the shipped LO 4.1.x then you should report it at http://bugzilla.novell.org/. It might be fixed and released as update for 13.1 then.
Me, I don’t feel the neccessity (not even for me) to have LibreOffice 4.2+ on openSUSE 13.1.
But I suppose I will upgrade to 13.2 as soon as it is available anyway… 
Oh no, -Tumbleweed and factory is not for casual folks.
But if you start to release the latest versions of the software as updates, you in fact create another Factory/Tumbleweed.
And that’s the whole point of Tumbleweed: to get the latest versions of software, but being more stable than Factory.
Evergreen is intended to be the exact opposite. Stay with the old proven versions of software, but still get fixes for security flaws and critical bugs. LO 4.2 won’t really fit into that I’m afraid.
That said, if you do want to see LO 4.2 in 13.1, you should file a feature request I guess.
http://features.opensuse.org/