As the title states. Already having to wait a solid 8-10 weeks on shards is bad enough for legendaries like Smourne and Valanyr, when phases are shorter than original wotlk.
But the huge problem with Smourne over Val anyr is all the added huge gold sinks and ressources dump.
25 primordial saronite is a massive problem as it stands as the first step of the questline, every guild in the game will be trying to get one and effectively cant get a hold of that many saronites for weeks if not more than a month (depending on how hardcore they are).
I suggest either moving the saronite requirement to a later part of the questline, such as after the ICC shard acquisition, as compensation. Meaning most people will have to slowly stock up the amount they need for legendaries with time and will allow it to be better spend on BOEs and much more during the start of the phase and not having people be several weeks behind on the legendary cause they didnt stock up on litterally 100s of thousands of gold or have a whole guild funnel them saronite through everyone donating all their emblems to buy em, which even though i would be able to afford it, it is still in my opinion stupid and pointless for classic as it is.
Or alternatively, just let players acquire shadowfrost shards from day 1 and it wont impact the length, when you finish that quest step, but will still require you to do it to get shadows edge.