Suggestion Unique items Tier 4

My idea is about unique items with tiers, such as Dragan set and the sets from PWs. What if tier 3 is
not the last (highest), what if there is a chance for us to combine four tier 3 items in tier 4 item on
the workbench???
I am thinking about adding a random enchantment to the item - all enchantments from tier 3 item remains
the same and one more is added, the new enchantment is one of the possible enchantments for the item
with a random value.
For example: a belt can have Hp, armor value, damage, crit damage, crit hit value or resistance, so if
i have 4 belts tier 3 from Bearach and i go for a tier 4 belt, I will get 650 crit hit value, 650
lightning resist, 305 Hp (the same like in tier 3) and 24 damage (the new enchantment, randomly picked
to be a damage line, and with random value)... Well, this may be not good for me, but that is my luck
... or maybe I will get 308 armor value, or 311 Hp - noone knows ... And the same thing with the other
items.
About the gems slots - the new item comes with four slots, even if one is with 5th slot added.
About the range of the values of the enchantments - well, a tier 3 item drops in fatal mode in PWs
(dragan set items a different, but anyways they can reached tier 3), so maybe the range of the value
can be the same like the range for a legendary item droped in fatal mode.
About an item leveled up with GoP, or items droped in lower levels and combined on lower level - soon
we will be able to take back GoP without loosing the item, so it is not a problem to have a condition
like all 4 items to be in the same level ... dont know how it works with dragan set items in lower
levels, I know that I can get level 39 item, or 43, but dont know what happens if I combine 3 level 39
and 1 level 43 item ... Maybe the same system will be used for lower level items ...
About the set bonuses - they remain the same, even if one item is upgraded to tier 4 and others are
tier 3, after all, tier 3 item is already a part of a set ... I was thinking for some procentage
increase of the bonuses when all items are tier 4 ... or maybe not, maybe will be to complicated ...
Maybe someone will say that this will be not fair, or an item will become OP ... maybe, but after all,
I can try again when I get 4 more tier 3 items, right, as every one will be able to do it too ... Or
maybe someone will say that is insane, why i have to keep 3 belts and for 4 months i didnt get the 4th,
waste of inventory space, waste of time ... OK, maybe, but noone force you to do it!!
Wish you good luck in real life and in game