Pretty much - I wear flannel in the fall almost exclusively. I find the mottled weave more interesting than most worsteds. Of course there are minor negatives. You may need a couple extra pair, as flannel should be rested two days after a wearing rather than just one, and they don't wear as well but in my opinion those defects are more than offset by the superior looks of a great flannel.
In spring, flannel trousers are progressively less desireable as the weather warms up. I have a pair in light (for flannel) ten ounce wool and they are not for temperatures much above 70 degrees (f) in my opinion.
I am entering into the business world and inherited some of my father's beautiful Oxxford clothing that fits me perfectly. However, all of the pants are pleated and it seems like that style has been phased out. Can I still wear them?
If you hang around here long enough you'll get tired of hearing that there is a difference between fashion and style. Fashion is for the fair sex, and shouldn't affect you unless you're dressing to go clubbing.
Savile Row still overwhelmingly prefers the pleated trouser, and for good reason. Pleats are more attractive on more men than flat fronts. Wear yours in good health.