I think some sort of letter pair system with chunks of visual memo mixed in or at the end is the best of all worlds.
I'm using a more phonetic based letter pair system right now. For each sticker I have strategically chosen a 1 syllable sound that consists of two letters. Right now about half of the combinations of any two syllables form real words. (eg: lo-go, go-ng, bo-ot). The rest require some association (eg: ot-og -> hotdog) but I am working on some ideas to cut down on these nastier cases like having multiple syllables associated with each piece(eg: DB can be ug or ng, which ever makes a nicer word.)
This is after I canned an idea for a grammatic system where every sticker would have a person, place, verb, adverb, adjective, conjunction, preposition, pronoun etc.. associated with it. Then I would memo in an order that fit a strict sentence structure like:
[adjective person adverb verb preposition adjective place conjunction etc...]
example sentence could be:
Sweaty James always goes under the supermarket but ...
got too complicated, required too many lists...it's just 3x3 edges...