The tram extension project is Picardy Place on stilts (probably shouldn't say that - might just give them ideas). I can see no realistic possibility of the project being "paused" or any community-led re-design. I genuinely think we need to work within what is going on.
Councillors need to be won over quickly, before officers get them thinking that nothing can be changed. I honestly think the best way of doing this is picture evidence from around Europe (Street view is good for this), showing well designed tram/walking/cycling streets and then simply saying "This is what we want, why are you proposing something less than what our international competitors are providing?".
In addition, the current designs need to be constructively criticised. To my mind there are a couple of decent lines of attack:
Equality Act 2010: Public sector equality duty - Public bodies have to consider all individuals when carrying out their day-to-day work. Removing pedestrian crossings, anti-pedestrian paving etc. are clearly detrimental to elderly and disabled people - definitely worth mentioning.
Policy: The street user hierarchy (walk, cycle, public transport, service vehicles, private car) - is set out in Designing Streets (http://www.gov.scot/Publications/2010/03/22120652/6), which feeds in to all local authority transport plans/strategies. The proposed design does not follow this hierarchy, or the policy priorities set out in the National Transport Strategy, Edinburgh Local Transport Strategy, Active Travel Action Plan, Edinburgh Transport Vision 2030 etc.
Pointing this out didn't help with Picardy Place, but there has to be some point to all these documents and I don't see much alternative.