What kind of reputation did Hooper have as a preacher?
Throughout the story, Hooper's reputation remains in good standing. The black veil does initially cast a weird and ominous vibe over Hooper, and most of the people in town would probably prefer him to take it off; however, his behavior and work as a pastor remained consistent even with the veil in place.
The sermon which he now delivered was marked by the same characteristics of style and manner as the general series of his pulpit oratory.
When we first meet Parson Hooper, he is described by the people as "good" and "gentlemanly." He is friendly to the people, and he nods "kindly" to them. He behaves in this manner throughout the rest of his life, and he has a solid reputation in the community. The veil hints at something ominous and sinister, but there is no doubt among the people that he leads a good and "irreproachable" life. His reputation for being a steadfast and good reverend is widely known throughout New England churches, and this is why Mr. Clark feels that the veil should finally be removed. He wants Hooper's "blameless" life to end without the shadow of the veil.
“And is it fitting,” resumed the Reverend Mr. Clark, “that a man so given to prayer, of such a blameless example, holy in deed and thought, so far as mortal judgment may pronounce. . .
I assume you are referring to Hooper's reputation prior to wearing the veil. His parishioners are shocked when Hooper puts on the veil because up to that point, he has been a conservative, ordinary minister, one that the congregation could respect. He behaved the way he was supposed to as a minister, concerned with the welfare of his parishioners and open to their advice. It's ironic that after donning the veil, Hooper seems to become a better minister, delivering more intense sermons.