playing champs like 
in lanes other then mid
IS NOT A FREE PASS TO BUILD FULL AP
THAT IS WHAT MID LANE IS FOR
stop acting like there are no items that give you ap and tank stats
just mix some of these with tank items and you can still do plenty of dmg and not get one shot
Rylais is bad on Lissandra and Liandry's is bad on Diana. But overall you're right. I've gone bruiser Diana with just hourglass and void staff before. It works well because a lot of tank items give you cdr which synergies with her shield really well. I'm not sure how good bruiser Lissandra would be though.
TBH i never cared who goes where in the team so long as said team has some of everything. If you have a Yasuo or a Riven mid, Sion jungle and Leona support, feel bloody free to go full AP Lissandra top, i dont bloody care. All i ask is that players contribute to the team, try to win and don't feed.
