I want to clarify that you can attain grade V guardians without spending money.  It takes time but once in a while a holy summoning bond drops as a reward when battling warlords.  I received one and summoned a grade V Conqueror... of course to enlighten and upgrade him you need many more bonds and stones which you're not going to get without spending money.

Mine is rank 6 level 30 and has a 52.3% pantheon attack bonus (Not enlightened and no skill stone enhancements)

https://gyazo.com/015538d71a94b49bf5fb947b62bd5018

Thank you for the clarification, Mikalosos. 

To your point and looking at your other maxed out guardians, it is apparent that you've spent a large amount of time and effort battling warlords, and yet  you've only won one grade 5 guardian (out of 14 types) from warlords throughout this time. So without spending a considerable amount of money, you will be at a 35% disadvantage on pantheons (still overwhelming), and a much larger disadvantage on all  other types that you haven't won a grade 5 guardian for. 

Lucifer HBG said:

1. Substantially reduce the power of grade 5 Guardians. 

2. Enable a path to acquire holy summoning bonds via emeralds and tournaments (not just the top 3)

As you can see from this snapshot taken from a recent battle report, players have already developed their grade 5 guardians to provide boosts upwards of 85% power to their units. This in my view dramatically disrupts the balance in the game, discouraging players from engaging in battles when their units are vastly weaker, as even grade 4 guardians that are maxed out can not attain anywhere near these boosts. 

In addition, non-coiners do not currently have a path to attain grade 5 guardians, even over time (something that has existed for nearly all other features you've introduced).  

Hello and thanks for your suggestions!

1. Devs won't change the balance of Guardians, Grade V.

Taking into account how hard it can be obtained and how many resources you need to fully develop it, nerfing its stats won't be fair to those players who already have their Grade V Guardians.

2. Devs plan to add Holy Bonds in rewards in tournaments, besides that they plan to use Holy Bonds in rewards in new game features.