I don't expect any answer, but this are some problems that I can think of that developers need to take in consideration if inventory limit will be implemented.
It's very hard to give an answer when an inventory limit is a theoretical attachment to the unnamed "randomised items" update, and therefore not at all developed to some definite stage. Here's the best I can answer, based more logic and expectation rather than fact, as right now the facts are there is no concrete facts but a jumble of opinions...
Then for adventurers (like me) who spend nuggets in premium just for the higher chance of getting an item (the rest of class bonuses are useless), will we get our nuggets back?
We used premium to get higher income (more $) then bought items, will we get our nuggets invested to have more items?
In short, no. Your items will be kept as collections, which will offer unique achievements and hopefully tangible rewards too, and/or [at least] the sell price of that item will be obtained...
I was just thinking, now if inventory will be limited what will happen with players that have more items that the limit?
I am not sure what the developers envision, but if I personally went about this I would give players a two week "amnesty" to convert items into their purchase price in cash. After this period ends, the inventory limit comes into force. Any excess items are automatically sold until the inventory is within the limit's bounds, in order of "general" items from least to most expensive then "special" items from least to most expensive.
Then there are players that bought with nuggets products, will we will receive our nuggets back?
Not sure if products are included in "randomised items", not sure if they will be fully included in inventory limit, unable to make comment at this stage. However, in the extremely unlikely final resort that refunding would be necessary, it would only be a logistical possibility for products brought directly through the relevant premium option.
Two posible solutions to the technical problem of storage space
1. create a record per player:
Player Id, item 1 quantity, item 2 quantity, item 3 quantity ... item 1000 quantity
where each item is fixed, eg item 1 = golden gun, item 2 = mustang etc.
so for 1k different items we would need a record per player of about 1 k in size.
there are approx 160k player so total space requirement for the table would be less than a gigabyte (if my maths are right)
2. Create a record per player / item
Player Id, item number, quantity (total of about 10 bytes)
If every player had a thousand items, this would require
160k players * 1k item types * 10 byte record size
which is about 10 gigabytes
There are advantages and disadvantages to both of the above solutions. The best option requiring an analysis on the mix of items per player
I think your "Option 1" is how it is handled presently, where each item is assigned an "Item ID" and stored in another database. This works fine when we have X number (say around 500) of unique items. A player's inventory is basically a two dimensional array of integers with item ID and quantity.
The problem arises when "randomised" and "customised" items are introduced. Say every player, roughly 150k, finds a single random item. This would mean our item database would jump from 500 entries to 150,000 entries! It's an over simplification for argument's sake, but it does show that allowing essentially infinite expansion of random items to occur just won't be technically viable in any capacity.