I have many  pragmatic concerns with the 'one state' solution every being anything other than the formalisation of Israel's  ethnic cleansing of greater Palestine/Israel.

Three  key musings come to mind.

1. Israel's continued existence in 'its current form' (read bulwark against Arab (sic) regionalism) is almost exclusively, by the USA in that it 'suits' * Their perceived* national interests i.e. a non dominated Muslim state in the Middle East. If this weren't so they wouldn't insist on being a party (3rd wheel) to any peace plan etc. As opposed letting Israel and Palestine (2 parties) as equal partners say with a Non aligned moderator.

The US fears a 'Muslim' Cuba so to speak, that is a Muslim influenced state( read a platform for Arab regionalism ) that might jeopardise their control (Commercial ?) over Middle Eastern OIL.

One should note here that the US has a long standing record of supporting Tyrannical regimes regardless of their religion so long as they can control the Tyrants that control the population. You pick the country from Central America, as much of Europe they can get away with, Asia generally (including Indonesia... west Papua), Middle East and even Africa. The common factor in all of these countries is their ( largely Commercial) interests. [ Specifics by request].

One should not forget three important points

1. Not all of which are 'Arab' states e.g. Iran is Persian and has a different underpinning culture and drives. Not all Muslims march to the same drum either religiously or in interests. The same as not not all “Christian” countries are the same.
2. That there is external non US forces playing Proxy games with Palestine, It is *these forces * that concern the US . This is by all regards a faux fear in that even if Iran had Nuclear bomb capability it doesn't really represent any existential threat as any aggressive attack would mean the total annihilation of Iran while the US would survive largely in tact. What it does mean is that the US simply won't be able to attack it at will.
3. It seems self evident that what Israel may want to do is largely irrelevant. The US will be the ultimate Authority to which Israel will ultimately accede. It has no choice, If it doesn't, one only needs to look at what happened to NZ when it insisted on knowing if US visiting naval ships visiting their ports  were Nuke armed. It's interesting to note that the US ignored the ANZUS treaty and refused to share 'intelligence', a clear misnomer (spin) read spying details. One can reasonably argue that the US doesn't display too much of that with regards to Non Americans. 
   Israel would not survive without US support and the US both knows this and WILL use that against them. As one of the US founding fathers aptly put it "any one who relinquishes freedom for security invariably gets neither'.
1. Subsequently, the 'one state' debate is largely both a distraction to the *main * stumbling block to a permanent solution ( changing the US' hard opposition to a Non Christian  aligned state.), one that gives hope for self determination and some modicum of Justice .
2. From a negotiating point this whole debate puts the Palestinians in a weaker negotiating position. Effectively made the first part of the Zionist/US for the elimination of the Palestinian as a self determined identity. The option (right or left) they will choose would be . And once it becomes official then the matter is an internal one and will be orders of magnitude harder to change. (they'll argue “ they (the Palestinians) negotiated this conclusion and we Israel (right wing version) have the right to seek out and deal with “internal dissenters”... any guesses what will constitute an “internal dissenter?

Rule 1. of negotiation Don't make a concession without getting an equivalent concession in return. Frankly the elimination of the two state option is a 'Huge' bargaining chip to give it away/ taken away before the negotiation begins.