A tram network for Leeds is much needed, but there are a few large caveats...
Firstly, I'd be very much opposed to converting any existing heavy-rail routes to tram (or tram-train, which seems to be the current darling of transport planners) because none of the currently open routes surrounding Leeds are really suitable for conversion: the vast majority also carry longer-distance traffic or freight. Secondly I'd be wary of things being done on the cheap, as happened in Sheffield resulting in renewals having to be brought forward.
Thirdly (and for now finally) the other councils in West Yorkshire will want their slice of the pie- which could result in longer-than-ideal routes into Bradford, Wakefield and Dewsbury which won't really compete with the private car... and will also create conflicts with the big bus groups, whom we know are not averse to making legal challenges on the grounds of unfair competition.
On that last point, until we sort out the regulatory side of things, any state-funded improvements will be hamstrung by our bizarre competition law which pitches different modes against each other rather than trying to integrate public transport as a whole.