I completely understand the "making supports more fun to play"... Support champs tend to vary in how fun they are and how to make the most out of them which is very well and good but the fact is those don't seem to apply to alot of people... But anyways heres just a few of my opinions on your suggestions/ideas...
Make supports stronger.
Firstly for this you would need to define a good baseline for what counts as a strong supp... which if you hadn't guessed wouldnt be easy cos of the number of varying opinions...
Then you need to draw everyone in line with that base line which in itself has some balance issues due to the difference in how supports play...
Give Supports gold income items that give sufficient gold as long as they don't farm.
^this I agree 100%... Supports need a better gold income... I mean they dont usually farm at all and the current gold boosts usually ten to leave us way behind everyone else if we don't take full advantage of every opportunity no matter how risky...
Get rid of items that sacrefice a lot of it's power to buff allies.
This I believe is a huge mistake... I mean you could just as easily buff the personal boosts these items give a little so its not a complete tradeoff... The reason for this is some support players like to take advantage of these items that provide boosts to their allies and by removing these you would be risking turning those people away from support.
But if you really want to bring in more supports what you really need to change is the community view of supports and people learning the ropes of support... The amount of times I've been raged at by an ADC for stealing farm cos my Sona Q accidentally took some of their farm or how many times some members of my team has expected me (while playing nami) to engage or even how if the ADC dies whatever happens half of the time its gonna be blamed on me or worst of all the ADC telling me how to play support and when what they tell me to do fails they get angry.... These kinds of experiences are usually what makes support an unpleasant role to play. If you really want more supports people need to be nicer to the ones we have.
On a side note... let people experiment with using champs that arent your "usual supports"... you might be pleasantly surprised... (key word there being "might")