I am so curious what Blaine's storyline in 501 is about. I think that arts funding spec is very plausible. I don't think all those choirs are getting together because Blaine wants to propose to Kurt.
I'm loving the songs they've chosen so far.
This is a Beatles tribute. In the Beatles movie Yellow Submarine, Blue Meanies (school board member and maybe Figgins) stop the music (show choir funding?) and the mayor sets in motion a plan to gather forces (Blam first asking the Warblers for Help!) to get the music back in Pepperland (Lima, Ohio). In the end, the huge, gathered forces defeat the Blue Meanies to the song All You Need Is Love. Hence there is the main plot and why Blaine is leading at least 2 group numbers.
The Klaine duet is probably just fanservice because of the proposal cliff hanger. (Which I think will be dropped for now.) And because they are the last of Glee's 4 core ships still able to be in play. Especially with the courtyard location, I'm not placing any meaning on Got To Get You In To My Life until proven otherwise. It might be just a recruiting song for new glee club members! Plus it gives titular leading man Kurt something to do other than be Rachel's personal cheerleader until they give him an arc. Coming in future episodes with Adam Lambert......