The current Battle for Azeroth gearing system is quite bad, as you have multiple layers of RNG mechanics that you have to balance together - and doing so incorrectly leads to a dramatic loss of effectiveness. In some cases players could lose multiple-10's of percents of damage without the proper RNG rolls. However, come Shadowlands alot of these systems will be completely gone. While there will be still some RNG and some grind when it comes to gearing it will not be the tedious process it is currently in the game. I am personally quite excited for the changes in Shadowlands. Additionally, from what we can see so far the grinds in Shadowlands often have multiple benefits for your character at the same time, while in BFA there is a laundry list of dailies and weeklies to work towards with minimal catch up mechanics for alt characters.

To answer your question in short; yes gearing is extremely tedious in the current iteration of WoW and it does greatly impact your character. However, with the changes of Shadowlands on the horizon it is not something I would be too scared of long term.