My Approach
Here's the thing about building a cube: it's YOUR cube. You get to choose every card that's in it, and as such, if you like or don't like a card, that's your choice of whether or not it gets in.
As such, this is my cube. It's full of cards I like that reflect the periods I was most active in the game. This includes Extended c. 2001-03 and Legacy c. 2013-2016.
This is fundamentally a legacy cube with a couple of powerful Vintage cards (Tinker, Mana Drain, Mishra's Workshop) added in for extra oomph. There's some fast mana (Mana Vault, Grim Monolith) but no real power (Sol Ring, Moxen). If there's a logic to the card choices, it's "Cards I Like." I want the broken cards to have drawbacks and my fair cards to be pushed.
Strategies
Rather than clear draft archetypes for each color combination, I designed the cube with the goal of making every meta-strategy (Aggro, Tempo, Midrange, Control, and Combo) viable across as many color combinations and strategies as possible. More specific strategies include:
Balancing is an ongoing process. Tempo was once extremely strong but I've cut a number of classic Delver cards - the current build is trying to reintroduce some of those elements.
Decor Choices
Old Border is king. Secret Lairs with truly unique art -- I mean art styles that feel like they're from outside the Magic world (as well as the greater TCG/anime world) are also prioritized. I love gold border cards, especially really weird ones like the ones from Mirrodin. Besides those, however, I can't stand new border (and the art style that came with it) and my goal is to have no new-border cards at all. Where that's not possible, I at least go for the full-art versions of the new-border cards.
Card Choices
The cube is mostly singleton except for a couple of limited exceptions:
My logic is that certain cards are so fundamental to the game that it benefits drafters to have an extra shot at them. The game already gives us two functionally identical Wrath of Gods -- why can't we have a third Wasteland and a second Dark Ritual?
Customization
Without making this into a full sharpie marker cube, I did add some limited errata to certain cards, which falls into three categories:
In all cases these are significant buffs. FoF at mana value 3 is better than Dig Through Time and way better than Stock Up, but that's OK, because that's how good Fact or Fiction seemed when it was printed in 2001, and I wanted to capture that that memory of being 12 years old and playing the best card draw spell in the game. Braids, by contrast, was pretty bad at 4 mana then and has always been pretty bad since, and yet people keep putting it in their cubes because they want it to be good. I tried it at 1BB and it was still bad; at BB it's finally competitive, and fits along with Liliana, Smallpox, and Sinkhole, and numerous enablers including Loam, Tokens, and Zombies. Kjeldoran Outpost, again, this card is unplayable without removing the drawback. Finally, I'm experimenting with this huge boon to Goblin Bombardment by drawing on contemporary card design, where there is no opportunity cost or drawback to anything. The sacrifice/aristocrats strategy has been very weak historically and this card is highly parasitic, so I'm trying to make it a sort of Up The Beanstalk that at the very least can cantrip. Finally, Icatian Javelineers is just this iconic card from Magic's past, that still isn't very good with vig and haste, but is definitely fun and playable with these two keywords.
I gave a few creatures new creature types to strengthen the Elf and Zombie tribal themes in the cube.
Evolving Wilds. I wanted the cube to have a unique feel and I am tired of the fetch-shock/fetch-dual play pattern of Modern and Legacy. In order to let drafters focus on their actual decks while drafting instead of keeping track of fetchlands, while still preserving all the other benefits of fetchlands in the game, I gave Evolving Wilds the errata of putting the basic into play untapped. There are eight copies of Evolving Wilds in the cube.