I always keep phones in cases. The OPO had a full wrap-around case which made it bigger. The OP2 had an intelligent idea of remove back panel and add a case which helped its size but still caused it to be wide. The OP3T (my current phone) had a metal frame and needed scuff protection, but since the OP3T the OP5 is bigger, OP5T bigger in the same metal frame concept so it is 3.4mm wider. In a one-handed mode your thumb has to stretch double the width to hold the phone and touch the far edge so its 6.8mm further to reach. 6.8mm is enough to change from just about able to touch the other side to impossible.
What I thought would happen is the bezel-less leaks was just more screen but no its just bigger. The laziest design change is when you add by making it bigger, any idiot can do that.