Welcome to the site !!
Sorry for a delayed reply , usually someone is on top of things around here , but somehow you got missed
Anyway ..... Not sure how you would favor a 230 over the old 400 , the weight difference will be great , but not sure you will be happy with the power delivery , or rather lack of it comparatively , I guess what the main factor is going to be is what type of riding you will be doing with it .... if its fire road trails , or tight single track and long steep hills , the 230 is going to struggle on the hills especially if you weigh over 150 or so , plus the suspension will be riding low in the stroke and that will give a harsher ride , so springs will be a added expense if you are not the right weight for the bike
I personally think , if you stay within the 250 range you would be happy power wise , but again , without knowing your riding habits , etc. its hard to suggest something you would be happy with and do what you need it to do , if its easy non technical trails with minimal steep hills , the 230 would be fine as long as you re-spring it for your weight , the downside to a 250X or so or even a 250L is you start getting near the weight of that 400 , so you are not gaining a advantage there , but , you will have better suspension and if you chose the 250L or the 250X then you would have a E-Start , so that kind of makes up for the extra weight , because you dont have to kick it when/if you fall or mess up , and the power would be much better overall than the 230 ......
There is no perfect answer anyone can given this situation as there are variables to consider , but I should ask ..... Have you ridden a 230 ?? , and was it just on flat ground ??? , have you ridden any of the other bikes in that class ?? ... Have you thought about a 2 stroke ?? (of any brand) , as the YZ250X is a excellent trail bike and will have tons of power and be pretty light , then there is KTM , etc. , but some people don't like 2 strokes , and/or regulations make it not worth the hassle , plus you need special gas , you can't just siphon some out of your buddies bike 30 miles back on some trail if it has no oil in it , I guess it boils down to your specific needs , I am older (will be 60 in Aug) and I understand the weight of the bike factor , I have a 450X and with the 3.2 tank , it weighs in right around 285 lbs , that is a lot of weight to pick up when your old and wore out , the button helps when starting , but you still feel the weight in the slow stuff or when picking it up off the ground
Anyway , hopefully I gave you some options to think over , or if you give more specifics , someone here might be able to steer you colser towards the right bike ....