Nowadays, it matters a lot.
Depending on the map, there are lanes that you want to weaken faster than the others, or defend more than the others.
Also, the meta is more like a 1-4 team where the solo either roams two lanes and the four pressure another lane, or the solo keeps soaking a lane and the four are roaming around the map to gather XP
You also want to time your merc camps to apply pressure right before an objective pops out.
Let me give some examples
- Tomb of the spider queen's high priority lane is the top lane because of the boss, and then, it's bottom lane because of the giants - Here, you either want a 1 top 4 roam mid-bot, or a 4 roam top-mid 1 bot
- Cursed Hollow top priority lanes are top and bot because of boss and giants pressure, mid is just so-so - here, 1-1-1 and two roamers are fine, you just have to be able to get the your giant camp before the first objective pops if you want it so badly
- Warhead Junction's high priority lanes are top and bot as well, for the same reasons as Cursed Hollow... Once that lane is clear, boss pressure will be dangerous for the enemies, and those are the only lanes pushed by mercs
- For Dragon Shire, you want your solo to be top because it is quite dangerous to retreat on that straight line bridge before your keep entrance, you wouldn't want to lose more than a hero when getting ganked by surprise
- Garden Terror has no particular priority lane as each one can be equally pressured by mercs
- Blackheart's Bay, the best laning is a 1 top-mid and 4 bot as most of the fights will happen near Blackheart
- Sky Temple, bot lane
- Volskaya Foundry, top lane
- Towers of Doom, bot lane, then top, because of the sappers who can deal damage to the core
- Infernal Shrines, top lane
- On two lane maps, you just want to match the number of enemy heroes on each lane
This is just another way to see the macro game, maybe someday, these strats may change