I would welcome people who change their party status. I would hold some suspicion though.
Republicans and Democrats hold some pretty fundamental differences in the way they see things.
My father was a Republican when he was younger. He came to the US when he was 16 as an immigrant from Mexico. He worked and went to school, joined the military and fought in Vietnam. He supported Nixon and the "silent majority" and did not like the protesters. He thought that LBJ got us into the mess and Nixon got us out. He thought Reagan was right in "never apologizing for America". However, around the second term of Reagan, he started noticing that what Republicans say they want, and what they do are very different. He saw that Reagan sold missiles to Iran (our enemy) and that Reagan was sending money to Nicaragua illegally. He changed his party affiliation in 1992. After learning what Republicans did he had to admit, at least to himself, that they were wrong and he was wrong in supporting them.
Republicans (at least the leadership) want government to enforce the existing social and economic order. They believe that capitalism and the free market can address all of the problems in society and that government need only get out of the way and protect private property to allow that to happen. Republicans think that the way things are right now are the result of people's choices and actions and that poor people have done or have not done something, and that is why they are where they are. They are okay with charity but they do not want their tax money going to "lazy people" (mostly what they think of Black and Brown people, when Brown people aren't stealing their jobs for lower pay).
Democrats want government to manage the excesses of capitalism through regulation and progressive taxation so that he benefits our our economic output makes everyone's life better. Democrats tend to recognize that inequality is the natural progression of unregulated capitalism and they want rules to keep that inequality from getting too bad. We too tend to believe in meritocracy, but many of us recognize that there are built in, longstanding, institutionalized forms of discrimination that have taken opportunity away from many. We don't like taxes either but understand that when people's basic needs are met and people have money to spend, that the economy and society fare much better.
My concern is that many Republicans see Trump as an aberration of Republicanism. They still support the values above, but see Trump as being gross and too racist, sexist, vulgar, etc.... He is all of those things, but my question is this: Trump always appeared to be more aligned with the Democratic Party. As a "rich" guy he went with whoever could do more for him economically but he favored Democrats. WHY DID HE RUN AS A REPUBLICAN AND NOT A DEMOCRAT? The answer is that he could NEVER have been elected as a Democrat because his views are repugnant to Democratic principles. Trump's policies are in line with Republican policies. The party has been right wing since the gilded age but shifting rightward socially since Nixon. The Republican Party is the party of hierarchy, decided by race, religion, gender, and wealth.
I do welcome people who have had a change. We just need to make sure they understand what they are joining.