Why is the Coalition in such a rush?

About everything. 
After the farce of a 'public consultation' over the issue of same-sex marriage, we now seem to have the prospect of rushed-through legislation on the subject of monarchical succession [here] - again, hardly something which is at the top of the average person's list of priorities in the midst of the worst economic recession since the Second World War. 
We could, of course, ask the question as to how exactly is the ending of male primogeniture any more 'logical' or 'equal'  then the ending of primogeniture itself? Both are the result of an 'accident of birth,' as, of course,  is the very  institution of monarchy. If we are desperately searching for a kind of à la mode pseudo-radicalism, then why not adopt the Anglo-Saxon model of an election within the Royal Family - something which would be fully consonant with the equally irrational notion of 'equality'  which currently holds sway among our governing political elites?
The answer to all this is - naturally - the business of raw politics. If you are unsure of what to do about matters of substance,  floundering in indecision or plagued by internal divisions, then for God's sake do something, anything...whatever...
The idea of leaving things alone, or giving time for a carefully considered response, taking into account the constitutional implications of any proposed change is, naturally, not on the agenda. 
The world began, after all, in 1968 - for 'conservatives' and 'liberals' alike...