i go back and read ur post from 1st page. it seem we are talking about different topic.

when i refer to focus, and i think when ramazan refer to focus, we are talking about months of play or maybe even years depending how long the game last.

let us take a scenario. in a month u farm enough to create 10 weapons that give atk skill with 2 uncaps with lv10 skill. i use those number because it about halfway point for damage potential progression, but since it much harder to level weapon to full uncap and lv20 skill, it is much shorter and more reasonable goal.

so, these 10 weapon that give about 1000 ATK and 8% ATK. there are two scenario here

1- if u put ur resources equal into all element to 'develop weakest team', let be generous with 10/6 and say u have 2 weapon for each element. that give u 16% bonus ATK, plus element advantage u get 61% bonus.

2- if u put ur resources all in 1 element, and u have 10 weapons with 8% ATK, from weapon skill alone already u getting 80% weapon bonus, meaning u outdamage on neutral element.

advantage of situation 1 is
take less damage because of element advantage
much easier to land debuff on weak element enemy

advantage of situation 2 is
easier to build party. u know ur healer or tank or buffer lineup wont change much because u using 1 element for almost everything
easier to build friends list with relevant element boost
more damage from same amount of gear for 5 of 6 scenarios other than vs strong element enemy

remember, we are discussing long term investment. so until and unless devs add higher rank of raid or repeatedly farmable loot, the weapons u want for weapon grid progression are ATK SR weapon from raid boss, which is only 1 of 3 weapons for each raid boss element, and low chance to drop.

i not telling u how to play game, but in my opinion, either u focus 1 element, or u lose out long term. there is reason DMM kamihime player run single primary element grid. same way there is reason most non-whale granblue player run single primary element grid.

actually, it funny but gbf progression guide apply significantly to kamihime although the name are different and many system are simplified or erased. i cannot link because forbidden, so google xiei progression guide ver alpha

Good Jobs for the MC – Your main character is the Mary Sue of this story and is one of the most powerful characters in the game. They will be your glue that holds your team together by providing synergy with your other characters or covering for their weaknesses. They also posses raid-wide abilities, which are the cornerstone of cooperative game play.

+

Good Characters for your team – Even with delicious ingredients, you need cooks to make delicious food. Similarly, you need good characters to take advantage of your good weapon pool. You’ll want a nice toolbox of characters to round out your team with important skills necessary for buffing your team, debuffing the enemy, dealing damage, reducing damage, or healing, depending on what the situation calls for.

+

A relevant Main Summon for your team – Your Main Summon (as well as the Support Summon chosen on the pre-battle screen) provides a passive Aura (JP: Divine Protection) effect for your team as well as improves your team’s base stats. These effects greatly magnify your weapon’s and character’s abilities and a good team without a Main Summon will lose out on a number of really important benefits. They can also be summoned in battle for useful Call effects as well.

+

Useful Sub Summons for your team – Your Sub Summons improve the base stats to your party members when equipped. While they do not provide the passive Aura that a Main Summon does, they can also be summoned in battle for many useful Call effects just like the Main Summon.

+

High base stat weapons for your Weapon Grid – The HP and ATK value of your weapons translates directly to your character’s base stats. Having bigger numbers in your Weapon Grid will give you bigger numbers for your characters while in battle.

+

High level Weapon Skills for Weapon Grid – The majority of weapons in Granblue Fantasy possess Weapon Skills that can improve various parameters for your characters. By filling your Weapon Grid with weapons that have synergistic Weapon Skills, you will be able to field characters that deal significantly more damage or have significantly more sustainability.

=

Everything you need to get stronger – While this seems like a lot to process, in practice this is not very difficult. By improving any one part of these 6 major factors, you can strengthen your team. By improving all 6 major factors, you can reach high level content.
two main point is, it is talking long term investment, and everything in the game is multiplicative so stacking will result highest numbers.

again, i hope my english not too confusing.