I don't think Tom and Mary will end up together, the ick factor is too high. I think the actors have chemistry and maybe they're banging between scenes but it's the wrong move for the show. Tom would never betray Sybil's memory like that. Matthew is also a factor but I believe marrying your dead wife's blood sister is a great deal more shocking. Imagine explaining that to Sybbie. "Well, honey your new mommy happens to be your aunt, so that makes your cousin George your step brother as well"... No. Even back then that kind of marriage was rare and extremely awkward for the family.
But I have to agree that Tom and Mary's suitors have been terrible. Lord G was boring, not surprising that he couldn't captivate in the bedroom. Mary truly dodged a bullet there. Charles Blake was better but he was like a hostile Matthew and didn't contribute much as a new personality. I liked the pig scene but otherwise, he was also rather uninspiring. Matthew Goode's character is interesting because he's Matthew's opposite in every way. He's sauve, impractical, impulsive, and brings out Mary's love of sophistication. Also, Michelle Dockery clearly thinks he's hotty and who can blame her? But I think he may be trouble. Not only is he a little too smooth, he has no money (screams fortune hunter) and a love of fast cars. They need to address that, so far Mary hasn't reacted, despite the fact that her beloved Matthew was killed in a car crash only 4 years prior.
Tom on the other hand, has had it really bad. The first liason after marriage was with a scheming maid and nearly brought shame on the family he's learned to love. She was a nasty piece of work, glad Mrs. Hughes took care of that. Then came Sarah Bunting, who at first appeared awesome. She had a lot in common with Tom and intellectually, she could keep up. I liked her. Then came the dinners. She was rude to his entire family on multiple occasions, in their own home. While I strongly sympathize with her views, she was quite nasty about it. Tom was passionate and expressed himself but he never personally attacked anyone with his views, except once when he was drugged. Or that time he tried to dump something gross on a military man but that was more comical and he did eventually realize that he was acting foolish. Tom has always tried to make people understand his point of view but he's never been arrogant and he can agree to disagree. Miss. Bunting would incite the arguements, despite Robert's best attempts to be civil and even when Tom begged her to try to get along with his family, she refused. I don't know what she expected from him. That's his daughter's family. He wasn't going to rip her from them over differing political ideology. She never apologized for causing problems for him, she was full of herself to the end. It's too bad because she could have been a lovely companion for Tom.
Due to the fact that the series is ending, I don't think we're going to see Tom married again. I'm kind of hoping we skip it with Mary as well. Maybe for Edith but after Mary's wedding, Sybil's marriage, Edith being jilted at the altar, Rose's wedding drama, the Bates' marriage delays over a crazy ex, and now the Carson wedding, I feel like wedding overload, even though most of those story lines were great. I think we're running out of time for developing marriages and we should focus on the characters destinies as individuals. After all, the times were changing.